Satellite SwStr - History

Satellite SwStr - History

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(SwStr.: t. 217; 1. 120'7"; b. 22'9"; dph. 8'6"; cpl. 43;
a. 2 8")

The first Satellite, a wooden, side-wheel tug built at New York City in 1854, was purchased by the Navy at New York on 24 July 1861, and commissioned at the New York Navy Yard on 12 September 1861, Acting Master Joseph Spinney in command.

The next day, the ship sailed for the Potomac and reached the Washington Navy Yard on the 16th. That afternoon, she steamed back down river to join the Potomac Flotilla off the mouth of Occoquan Creek and began almost two years of operations in the roughly parallel rivers which drain tidewater Virginia and empty into the Chesapeake Bay.

Her first action came on 25 September when she was fired upon by a Confederate battery at Freestone Point; but, during the action, she suffered no casualties or damage. From that time on, her duels with artillery and riflemen hidden along the shores were frequent. On 18 October, the tug bombarded Confederate positions at Shipping Point, Va. On 15 November, a boat from the ship rowed down stream on a scouting expedition and returned before the following dawn with two scows and three skiffs as prizes. Two days
later, Satellite shelled positions below Boyd's Hole. On 7 December, four shells fired from Shipping Point passed over her deck between her pilot house and wheels. On the 22d, the sound of artillery from Boyd's Hole drew the ship downstream to investigate. She found a Union merchant schooner which had been disabled by the cannonade and, while assisting the damaged ship, came under fire herself. Two shells hit Satellite's wheel house without causing casualties or serious damage, and Satellite replied in kind, silencing her adversaries.

Similar action enlivened her service in the following months. Her log records three engagements in January 1862, one in February and eight in March. On 15 February, after a shell exploded in Harriet Lane's paddle box, disabling her as she passed Shipping Point, Satellite assisted the damaged revenue cutter.

On 13 April, with the other ships of the 2d Division of the Potomac Flotilla, Satellite sailed for the Rappahannock, under presidential orders, to gather intelligence on Southern forces in the area, and to neutralize any threat from that quarter to General McClellan's army which was then fighting up the peninsula, between the James and York rivers, toward Richmond. The next day, the Union ships shelled fortifications along the shore and landed boat parties to destroy Fort Lowry which Southern troops had abandoned. During their operations, the gunboats ascended the river to Tappahannock. On 20 April, Satellite and Island Belle captured sloop, Reindeer, and schooners, Sarah Ann and Sabine, all of Tappahannock.

In May, Satellite returned to the Potomac. On the 26th, while the ship was being repaired at the Washington Navy Yard, most of her crew traveled to Harper's Ferry, Va., to help defend that strategic post which was threatened by General T. J. "Stonewall" Jackson's brilliant operations in the Shenandoah Valley.

On 9 June, after repairs had been completed and her crew had returned, Satellite got underway for Fort Monroe to join Union naval forces on the James River in supporting McClellan's drive toward the Confederate capital. Soon after she reached Hampton Roads, the tug was ordered to protect a submarine, which, it was hoped, would be able to destroy the railroad bridge across the Appomattox River at Petersburg, and to clear the obstructions from the channel of the James below Drewry's Bluff. Satellite accompanied the submarine, which was later named Alligator, up the river

but Comdr. John Rodgers, the senior naval officer on the James, felt that the submarine would be unable to perform the underwater demolition missions. The shallowness of the Appomattox, he felt, would prevent her from reaching the bridge submerged; and a surface approach would expose the vulnerable craft to destruction or capture. In Confederate hands, Rodgers feared the submarine might seriously threaten northern warships. As for the obstructions in the James, Union tugs, Rodgers reasoned, might succeed in pulling the sunken, stone-laden lighters from the channel of the James. However if the submarine should succeed in destroying the hulks, their cargoes of stone would remain to obstruct navigation and would be almost impossible to remove while covered by Confederate guns. For these reasons, he sent the submarine back to Fort Monroe.

Satellite remained up river and, on 26 June, entered the Appomattox in a naval force led by Rodgers. The warships were impeded by musketry and obstructions. Finally, shallow water stopped them too far away from Petersburg to launch a boat attack against the railroad bridge. When efforts to refloat the grounded sidewheeler, Island Belle, proved futile, a party from Satellite stripped the tug and set her afire.

Following their return to the James, the gunboats supported General McClellan's army which was then fighting General Robert E. Lee's troops in the bloody Seven Days Campaign. In this series of battles, the Northern soldiers beat their way across the peninsula from the York River to the James where Rodgers' floating firepower could prevent Lee from closing his pincers. After he learned of the disposition of the Federal ships, Lee reported: "As far as I can see there is no way to attack him [McClellan] to advantage; nor do I wish to expose the men to the destructive missiles of his gunboats . I fear he is too secure under cover of his boats to be driven from his position . ."

During McClellan's retreat to Harrison's Landing, the Union Army'sgunboat-protected haven on the James, Satellite and Delaware ascended the Chickahominy River to strengthen his right flank. In the ensuing weeks, Satellite protected Union troops ashore and transports afloat, often engaging Confederate forces on the riverbanks. On 27 July, boats from Satellite and Yankee ascended Chippoak Creek and captured schooner, J. W. Sturges, and a schoonerrigged lighter laden with wood. They also found two other schooners and a steamer which had been scuttled before they arrived. In mid-August, after Union leaders had decided to abandon the peninsula, Satellite Galena and Port Royal covered the retirement as McClellan's rear guard withdrew across the Chickahominy toward Fort Monroe.

At the end of August, as Lee and Jackson routed a Union army under General Pope in the second Battle of Bull Run, Satellite and a large portion of the James River Flotilla were transferred to the Potomac to help protect the threatened Federal capital and its line of communications by water, the Potomac.

In mid-September, at Antietam Creek, Md., Gen. McClellan relieved the pressure on Washington when he stopped Lee's thrust into the North and forced the Confederate Army of Northern Virginia to retreat south of the Potomac. Nevertheless, the ships of the Potomac Flotilla were kept in the Potomac to try to stop communication and commerce across the river between Virginia and Southern sympathizers in Maryland. On 30 October, Satellite captured a canoe and five men off the Wicomico River, and, three days later she took a yawl near Neal's Creek. On 21 November the side-wheeler returned to the Washington Navy Yard with a number of prisoners who had been arrested for blockade violations.

On 29 November, as the Union's Army of the Potomac prepared to resume the offensive with a drive through Fredericksburg, Satellite departed Washington and headed for the Rappahannock to help assure the new Northern commander, Major General Burnside, control of that river. She remained on the Rappahannock after Lee skillfully parried Burnside's thrust at Fredericksburg in mid-December. On 2 January 1863 Satellite and three other Union ships steamed to the Piankatank River seeking a schooner which had run through the blockade and entered that stream. However, the Confederates learned of the expedition and scuttled the schooner before the Northern gunboats could reach her. In mid-January, Satellite returned to the Washington Navy Yard for repairs.

The following spring, the ship resumed activity on the Rappahannock hoping to support the Union Army's new offensive, but again Lee adroitly bested the Northern commander, now General Joseph Hooker and won an all-but-decisive victory at Chancellorsville. Nevertheless, Satellite continued to operate on the Rappahannock. From 12 through 14 May, she participated in an expedition which captured schooners Sarah Lavinia and Ladies Delight, and took a large quantity of goods from warehouses at Urbana. On the 21st, she joined Currituck and Anacostia in seizing schooner, Emily, at the mouth of the Rappahannock. A week later, she captured schooners, Sarah and Arctic, up the eastern branch of the Great Wicomico River, an estuary between the Rappahannock and the Potomac. With Jacob Bell and Yankee, she took a canoe and a flatboat on 13 July near the Rappahannock's Union Wharf. Satellite's last score came on 17 August when she captured schooner, Two Brothers, near the Great Wicomico.

On the night of 22 and 23 August 1863, a daring Confederate boat expedition commanded by Lt. John Taylor Wood, CSN-grandson of the former President of the United States, Zachary Taylor, and nephew of Jefferson Davis, the Confederate President-captured Union gunboats, Satellite and Reliance, off Windmill Point on the Rappahannock. Wood took the prizes up river to Urbana.

Satellite, now under Lt. Wood, returned to the mouth of the Rappahannock on the 25th and seized schooner, Golden Rod, laden with coal, and schooners, Coquette and Two Brothers, with cargoes of anchors and chain. The Confederates stripped and burned Golden Rod because of her deep draft and took the other prizes up river to Port Royal, Va. There, together with Satellite and Reliance, they too were stripped of useful parts and destroyed on 28 August to prevent recapture.

Satellite SwStr - History

Just as different seats in a theater provide different perspectives on a performance, different Earth orbits give satellites varying perspectives, each valuable for different reasons. Some seem to hover over a single spot, providing a constant view of one face of the Earth, while others circle the planet, zipping over many different places in a day.

There are essentially three types of Earth orbits: high Earth orbit, medium Earth orbit, and low Earth orbit. Many weather and some communications satellites tend to have a high Earth orbit, farthest away from the surface. Satellites that orbit in a medium (mid) Earth orbit include navigation and specialty satellites, designed to monitor a particular region. Most scientific satellites, including NASA&rsquos Earth Observing System fleet, have a low Earth orbit.

The height of the orbit, or distance between the satellite and Earth&rsquos surface, determines how quickly the satellite moves around the Earth. An Earth-orbiting satellite&rsquos motion is mostly controlled by Earth&rsquos gravity. As satellites get closer to Earth, the pull of gravity gets stronger, and the satellite moves more quickly. NASA&rsquos Aqua satellite, for example, requires about 99 minutes to orbit the Earth at about 705 kilometers up, while a weather satellite about 36,000 kilometers from Earth&rsquos surface takes 23 hours, 56 minutes, and 4 seconds to complete an orbit. At 384,403 kilometers from the center of the Earth, the Moon completes a single orbit in 28 days.

Changing a satellite&rsquos height will also change its orbital speed. This introduces a strange paradox. If a satellite operator wants to increase the satellite&rsquos orbital speed, he can&rsquot simply fire the thrusters to accelerate the satellite. Doing so would boost the orbit (increase the altitude), which would slow the orbital speed. Instead, he must fire the thrusters in a direction opposite to the satellite&rsquos forward motion, an action that on the ground would slow a moving vehicle. This change will push the satellite into a lower orbit, which will increase its forward velocity.

In addition to height, eccentricity and inclination also shape a satellite&rsquos orbit. Eccentricity refers to the shape of the orbit. A satellite with a low eccentricity orbit moves in a near circle around the Earth. An eccentric orbit is elliptical, with the satellite&rsquos distance from Earth changing depending on where it is in its orbit.

Inclination is the angle of the orbit in relation to Earth&rsquos equator. A satellite that orbits directly above the equator has zero inclination. If a satellite orbits from the north pole (geographic, not magnetic) to the south pole, its inclination is 90 degrees.

Together, the satellite&rsquos height, eccentricity, and inclination determine the satellite&rsquos path and what view it will have of Earth.


In Buchanan's own words, [1] the government of Paraguay had:-

  1. "[S]eized and appropriated the property of American citizens residing in Paraguay, in a violent and arbitrary manner"
  2. "upon frivolous and even insulting pretexts, refused to ratify the treaty of friendship, commerce and navigation"
  3. "fired upon the United States steamer Water Witch . and killed the sailor at the helm, while she was peacefully employed in surveying the Parana river".

The honor, as well as the interest of the United States, concluded Buchanan, demanded satisfaction. [2] [3] In his first annual message to Congress (8 December 1857) he said he would make a demand for redress, "in a firm but concilatory manner", but backed up by force if necessary.

On 2 June 1858 a joint resolution of Congress authorized the President to obtain satisfaction, using force if necessary." [4]

The adventures of Edward A. Hopkins Edit

Edward Anthony Hopkins was an adventurer who caused trouble with the government of Paraguay. As will appear, insofar as a single person could be to blame for the Paraguayan debacle, that person was Hopkins.

A former midshipman in the U.S. Navy who had been court-martialled three times and dismissed from his squadron, [5] he has been described as "undisciplined, imprudent, arrogant, aggressive", [6] "unruly, quarrelsome, pugnacious, and arrogant", [7] and "swaggering, bullying and tyranical". [8] According to yet another scholar,

Edward A. Hopkins was an unusual man and therein lay his difficulties. His outstanding characteristics were presumptuousness, egotism and marvellously bad judgment. These characteristics were combined with a lively imagination that Hopkins resorted to whenever reality became too cumbersome — which was most of the time! Hopkins managed to combine these characteristics in such an unusual manner that he antagonized everyone who had the misfortune of dealing with him. [9]

His first appointment to Paraguay Edit

In 1845 James Buchanan, at that time Secretary of State, needed to appoint a confidential agent to visit Paraguay, so he could determine whether it was worth granting diplomatic recognition. The man Buchanan chose for the job was the 22-year old [5] Edward A. Hopkins. Despite his unpromising record, Hopkins got himself appointed, through family influence. [7]

Hopkins had no diplomatic status. His sole functions were to communicate American goodwill and to report the facts on the ground to the U.S. government. He soon exceeded his remit, not only trying to mediate a longstanding dispute between Paraguay and Buenos Aires dictator Juan Manuel de Rosas — falsely claiming he had U.S. authorization to do it — but making wild and intemperate proposals. [10] When Rosas paid no attention, Hopkins wrote him a letter that was so insulting the United States felt constrained to apologize. Hopkins was recalled. [11] [12] [13]

His second appointment, and his rejection by Paraguay Edit

Hopkins was a persuasive optimist. [7] He persuaded prominent Rhode Island investors, including Governor Samuel G. Arnold, that Paraguay was an excellent business opportunity. [14] They incorporated the United States and Paraguay Navigation Company. With a capital of $100,000, it would build and sail ships on the rivers of South America as well as conduct other business. Hopkins had himself appointed U.S. Consul in Paraguay, a diplomatic post he secured despite his calamitous record: he was the only applicant. [15] He assumed office in June 1853. He was also the general agent of the Rhode Island company in Paraguay. [8]

The business venture of the United States and Paraguay Navigation Company was a failure. Its main asset, a steamship loaded with machinery and merchandize, was shipwrecked well before it could get to Paraguay. [15] Salvaging the cargo as best as he could, Hopkins arrived in Paraguay and borrowed 11,500 pesos [16] from its president, Carlos Antonio López. [17] Hopkins started a sawmill and a cigar factory which — thanks to López — were allowed to operate on favorable terms, e.g. they were manned by cheap conscript labor. The commercial viability of the venture entirely depended on the goodwill of López. [18]

President López was an irascible, corpulent dictator [19] [20] furthermore, a micromanager. [21] Even so, he is now acknowledged as one of Paraguay's better rulers — a modernizer. [22] [23] [24] López was gradually bringing Paraguay out of its long period of isolation. Because their country had an insecure history, Paraguayans were xenophobic and touchy. In colonial times Paraguay had had to struggle against endemic Indian and Portuguese raids [25] after its independence, with Brazilian [26] and Argentine [27] bullying. Dealing with López called for diplomatic tact and patience [28] yet the man entrusted with the task was Edward A. Hopkins, whose arrogance began to irritate the President. [16] Hopkins "made no secret of his mission to 'civilize' Paraguay". [8]

One day Hopkins' brother and the wife of the French consul were out riding in the countryside when they encountered three Paraguayan soldiers herding cattle. The soldier in charge ordered the couple to move aside so as not to frighten the animals, but he was ignored and the cattle stampeded. Enraged, the soldier struck Hopkins' brother with the flat of his sword. Whereupon, wrote Professor Ynsfran

Consul Hopkins, instead of lodging a reasonable complaint with the police on behalf of his brother, presented himself in riding boots and flourishing a whip in the hand at the government house, where he was admitted as usual with every consideration, and confronted the president with a shower of vituperations and threats. The flabbergasted ruler was for the moment speechless. After a few minutes he recovered his calm and dismissed Hopkins with the admonition that if he had any remonstrances he should present them through the proper channel. Hopkins had conjured up his own Nemesis. President López, incensed at this gross conduct, withdrew Hopkins' exequatur, and the latter had no alternative but to leave the country. This meant the shattering of the inchoate emporium of the Rhode Island company. [29]

A different source found that Hopkins boasted that he "forcibly entered the audience chamber of President López, in his riding dress, whip in hand, despite the remonstrance of the guard". [30]

Hopkins made it worse. Even though López had ordered the soldier to receive 300 lashes for exceeding his authority, [31] Hopkins demanded that Paraguay apologise in its official newspaper. [32] He possessed certain documents which he was supposed to deliver up before leaving the country. He refused, and in defiance of López was conveyed out of Paraguay aboard a visiting American vessel USS Water Witch. An infuriated López banned all foreign warships from entering Paraguayan waters. This incident, and the role of Water Witch in further exacerbating American-Paraguayan relations, will be described later.

The claims of the Rhode Island company Edit

Back in the United States the company that Hopkins represented got up a claim against Paraguay. This claim was afterwards adjudicated, see below, by a two-person international commission comprising an American and a Paraguayan arbitrator. The arbitrators agreed that the Rhode Island company's claim was worthless. However, this was not determined until August 1860. Meantime, the Rhode Island company got up a campaign. It asserted that it had been wronged and damaged by the Republic of Paraguay to an amount in excess of a million dollars. It was in reference to this claim that President Buchanan said Paraguay had "seized and appropriated the property of American citizens residing in Paraguay, in a violent and arbitrary manner".

Summary Edit

The claim by the Rhode Island company that they were arbitrarily ruined by the Paraguayan government, later adjudicated as worthless, was, therefore, one of the three official causes for sending the Paraguay expedition.

Refusing to ratify the friendship treaty Edit

Paraguay had a history of feeling disrespected by its larger neighbors Brazil [26] [33] and Argentina [34] [35] ` and welcomed recognition by third countries. [5] Recently, in 1853, Paraguay had negotiated treaties of friendship, commerce and navigation with Great Britain, France, Sardinia [36] and the United States, [37] and looked forward to the ratification of the latter by the U.S. Senate. These four treaties were almost word-for-word the same, [38] [39] and contained most favored nation clauses.

Owing to the carelessness of a visiting American diplomat, many formal mistakes got into the wording of the U.S.-Paraguay treaty, e.g. the U.S.A. was referred to as "United States of North America" so the U.S. Senate required these be corrected. A corrected version was prepared for Paraguay to ratify. [38] By the time the document arrived in South America consul Hopkins had departed, and no American diplomat was available to formally present it to the Paraguayan government. So the responsibility was given to Lieutenant Thomas Jefferson Page, commander of USS Water Witch [40] [41] [38] [42]

Following the Hopkins incident in which he was conveyed out of Paraguay by USS Water Witch (September 1854), an angry President López was in no mood to ratify, and Water Witch had been banned from Paraguayan waters. Lieutenant Page sent an officer to Asunción by commercial steamer to hand-deliver the corrected version of the treaty. However, an upset Paraguayan government refused to receive it because it was not in Spanish. [43]

Summary Edit

Buchanan complained Paraguay refused to ratify the treaty "on frivolous and even insulting pretexts". But strictly speaking Paraguay was not bound to ratify a document not in its national language more to the point, it was not bound to ratify a treaty of friendship at all still less, if there was not friendship enough. The upshot, however, was that while France, Great Britain and Sardinia had gained commercial and navigation advantages, the United States had yet to do so.

That, then, was another of the three reasons Buchanan gave for sending the Paraguay expedition.

USS Water Witch Edit

Water Witch was a ship of the United States Navy that explored the rivers of the River Plate basin. These rivers drain an area of land equal to one-fourth of the surface of South America. Amongst the most important are the Paraná River and the Paraguay River. They are accessible through Argentine territory.

In 1852 dictator Rosas — who used to block access to them — was overthrown and his successor Justo José de Urquiza opened the rivers of Argentina to free navigation by the ships of all nations. The United States therefore decided to send Water Witch on an expedition of scientific exploration, intended to encourage commerce and enhance American prestige. [44]

USS Water Witch was the best vessel for this role. Launched in 1852, she had a wooden hull 150 foot long, a 22-foot beam, and drew only 7 feet 10 inches, important for navigating rivers that were liable to shoal. She carried an experimental propulsion system (Morgan eccentric feathering paddle wheels). [45] Rigged as a topsail schooner, she was armed with three small bronze howitzers. [46]

She was commanded by Lieutenant Thomas Jefferson Page USN, who afterward wrote an accessible account of her voyages. [47] Born into one of the First Families of Virginia, his grandfather had signed the Declaration of Independence. However, Page was wanting in tact, [48] and was no diplomat. [49] In touchy Paraguay misunderstandings could occur, yet according to the southern gentleman honor code, insult literally could not be tolerated. [50]

President López welcomes USS Water Witch Edit

Water Witch arrived at Asunción in October 1853. At this time consul Hopkins had only been in Paraguay a few months and was still on good terms with President López.

Lieutenant Page wrote that López received them very well, concluding [51]

the reception of the expedition in his waters, and his entire course towards us, until his outbreak with [consul Edward Hopkins], was characterized throughout by generous hospitality.

Since Paraguay sought American friendship, it was understandable.

First dent in American-Paraguayan relations Edit

Page wanted to take Water Witch up the Paraguay River into the Mato Grosso, owned by Brazil, and applied to López for permission. However, there was a highly sensitive political situation that Page did not fully understand:

Paraguay had a tense relationship with the Empire of Brazil the two countries had a 300-year old, shifting boundary dispute going back deep into colonial times. [26] Where Paraguay ended and Brazil began was strongly disputed, and had led to firefights. [52] [53] Paraguay considered that Brazilian settlers from the Mato Grosso were continually encroaching into and appropriating Paraguayan territory, [54] yet López could not persuade Brazil to sign a definitive boundary agreement. [55] He felt very bitter about this. [56] López feared to make a precedent whereby Brazil would demand the right to navigate via the River Paraguay into the Mato Grosso.

What was really at issue was Lopez's fears that free navigation would lead to an enormous Brazilian buildup in the Mato Grosso which would threaten Paraguay militarily, and, through its commercial impact on the North, would especially increase smuggling. It would seem that López had an almost morbid premonition that formal war with Brazil was on the cards. [57] .

Accordingly, López issued Lieutenant Page with a passport to explore the Paraguay River up to a certain point, [58] but no further. [59] [60] [61] When Water Witch arrived there, however, Page persuaded himself he could ignore López's prohibition and he pushed on deep into Brazilian territory. Scientifically, this was interesting politically, reckless. Page established his 450 ton ship could steam up to Corumbá in the Mato Grosso, 1,870 miles from Buenos Aires, further than had ever been done before his achievement opened up the Mato Grosso to steam navigation (far and away the best means of access to the province) [62] [63] but he upset López. Although López tried to be polite about it, it was a dent in American-Paraguayan relations. López no longer trusted Page. [64] [65] [66] [67]


Satellites by launch date Edit

Satellite Launch (UTC) Carrier rocket Launch site Block No. SVN PRN Slot Status
OPS 5111 22 February 1978
Atlas E/F SGS-1 VAFB, SLC-3E I 1 [2] 01 04 Retired
17 July 1985 [3]
OPS 5112 13 May 1978
Atlas E/F SGS-1 VAFB, SLC-3E I 2 [4] 02 07 Retired
16 July 1981 [3]
OPS 5113 7 October 1978
Atlas E/F VAFB, SLC-3E I 3 [5] 03 06 Retired
18 May 1992 [3]
OPS 5114 11 December 1978
Atlas E/F VAFB, SLC-3E I 4 [6] 04 08 Retired
14 October 1989 [3]
Used for testing between February 1990 and May 1990. [3]
OPS 5117 9 February 1980
Atlas E/F VAFB, SLC-3E I 5 [7] 05 05 Retired
28 November 1983 [3]
OPS 5118 26 April 1980
Atlas E/F VAFB, SLC-3E I 6 [8] 06 09 Retired
6 March 1991 [3]
(Navstar 7)
19 December 1981
Atlas E/F VAFB, SLC-3E I 7 07 10 N/A [3]
Failed to reach orbit
OPS 9794 14 July 1983
Atlas E/F VAFB, SLC-3W I 8 [9] 08 11 Retired
4 May 1993 [3]
USA-1 13 June 1984
Atlas E/F VAFB, SLC-3W I 9 [10] 09 13 Retired
20 June 1994 [3]
Used for testing between February 1994 and June 1994. [3]
USA-5 8 September 1984
Atlas E/F VAFB, SLC-3W I 10 [11] 10 12 Retired
18 November 1995 [3]
Used for testing between November 1995 and March 1996 [3]
USA-10 9 October 1985
Atlas E/F VAFB, SLC-3W I 11 [12] 11 03 Retired
13 April 1994 [3]
(Block II prototype)
II 0 12 N/A
Qualification vehicle built by Rockwell International to secure Block II contract never launched.
USA-35 14 February 1989
Delta II 6925-9.5 CCAFS, LC-17A [13] II 1 [14] 14 14 Retired
26 March 2000 [15]
USA-38 10 June 1989
Delta II 6925-9.5 CCAFS, LC-17A [13] II 2 [16] 13 02 B3 Retired
22 February 2004 [15]
USA-42 18 August 1989
Delta II 6925-9.5 CCAFS, LC-17A [13] II 3 [17] 16 16 Retired
13 October 2000 [15]
USA-47 21 October 1989
Delta II 6925-9.5 CCAFS, LC-17A [13] II 4 [18] 19 19 A5 Retired
16 March 2001 [15]
USA-49 11 December 1989
Delta II 6925-9.5 CCAFS, LC-17B [13] II 5 [19] 17 17 D3 Retired
23 February 2005 [15]
USA-50 24 January 1990
Delta II 6925-9.5 CCAFS, LC-17A [13] II 6 [20] 18 18 Retired
18 August 2000 [15]
USA-54 26 March 1990
Delta II 6925-9.5 CCAFS, LC-17A [13] II 7 [21] 20 20 Retired
21 May 1996 [15]
Decommissioned after twice changing frequency without being commanded to.
USA-63 2 August 1990
Delta II 6925-9.5 CCAFS, LC-17A [13] II 8 [22] 21 21 E2 Retired
25 September 2002 [15]
USA-64 1 October 1990
Delta II 6925-9.5 CCAFS, LC-17A [13] II 9 [23] 15 15 D5 Retired
17 November 2006 [15]
Used only for testing from November 2006 until March 2007 [15]
USA-66 26 November 1990
Delta II 7925-9.5 CCAFS, LC-17A IIA 1 [24] 23 23
E5 Retired
25 January 2016 [25]
Decommissioned from active service using PRN23 on 13 February 2004. Set usable with PRN32 on 26 February 2008. [15]
USA-71 4 July 1991
Delta II 7925-9.5 CCAFS, LC-17A IIA 2 [26] 24 24 D1 Retired
30 September 2011 [27]
USA-79 23 February 1992
Delta II 7925-9.5 CCAFS, LC-17B IIA 3 [28] 25 25 A2 Retired
18 December 2009
USA-80 10 April 1992
Delta II 7925-9.5 CCAFS, LC-17B IIA 4 [29] 28 28 C2 Retired
15 August 1997 [15]
Retired early, replaced by USA-117.
USA-83 7 July 1992
Delta II 7925-9.5 CCAFS, LC-17B IIA 5 [30] 26 26 F5 Retired
6 January 2015 [31]
USA-84 9 September 1992
Delta II 7925-9.5 CCAFS, LC-17A IIA 6 [32] 27 27 A6 Retired
10 August 2011 [33]
Final command and disposal on 18 April 2017.
USA-85 22 November 1992
Delta II 7925-9.5 CCAFS, LC-17A IIA 7 [35] 32 31
F4 Retired
17 March 2008 [33]
PRN changed from 32 to 01 in January 1993 due to receiver problems. Decommissioned 17 March 2008 and removed from slot F4. Briefly resumed L-band transmission in 2014 but signal unusable. [15] [33]
USA-87 18 December 1992
Delta II 7925-9.5 CCAFS, LC-17B IIA 8 [36] 29 29 F5 Retired
23 October 2007 [37]
USA-88 3 February 1993
Delta II 7925-9.5 CCAFS, LC-17A IIA 9 [38] 22 22 B1 Retired
3 December 2002 [15]
USA-90 30 March 1993
Delta II 7925-9.5 CCAFS, LC-17A IIA 10 [39] 31 31 C3 Retired
24 October 2005
USA-91 13 May 1993
Delta II 7925-9.5 CCAFS, LC-17A IIA 11 [40] 37 07
C4 Retired
18 March 2016 [41]
Switched to PRN01 in October 2008 but was unusable. [15] Switched to PRN24 in April 2012 but was unusable. [42]
USA-92 26 June 1993
Delta II 7925-9.5 CCAFS, LC-17A IIA 12 [43] 39 09 A5 Retired
19 May 2014 [33]
USA-94 30 August 1993
Delta II 7925-9.5 CCAFS, LC-17B IIA 13 [44] 35 05
B5 Retired
10 June 2016 [15]
Decommissioned from active service using PRN05 in March 2009. Resumed activity using PRN30 in August 2011. [15]
USA-96 26 October 1993
Delta II 7925-9.5 CCAFS, LC-17B IIA 14 [45] 34 04
D6 Disposal
20 April 2020 [46] [47]
Decommissioned from active service using PRN04 in November 2015. [48] Reactivated in March 2018 using PRN18. [49] Decommissioned from active service using PRN18 in October 2019. [50]
USA-100 10 March 1994
Delta II 7925-9.5 CCAFS, LC-17A IIA 15 [51] 36 06
04 [52]
C6 Retired
21 February 2014 [33] [34]
USA-117 28 March 1996
Delta II 7925-9.5 CCAFS, LC-17B IIA 16 [53] 33 03 C5 Retired
2 August 2014 [54]
USA-126 16 July 1996
Delta II 7925-9.5 CCAFS, LC-17A IIA 17 [55] 40 10 E6 Retired
11 March 2016 [56]
USA-128 12 September 1996
Delta II 7925-9.5 CCAFS, LC-17A IIA 18 [57] 30 30 B2 Retired
20 July 2011 [33]
17 January 1997
Delta II 7925-9.5 CCAFS, LC-17A IIR 1 42 12 N/A [33]
Failed to orbit.
USA-132 23 July 1997
Delta II 7925-9.5 [58] CCAFS, LC-17A IIR 2 43 13 F6 Operational [33]
USA-135 6 November 1997
Delta II 7925-9.5 CCAFS, LC-17A IIA 19 [59] 38 08 A3 Retired
9 October 2019 [60]
USA-145 7 October 1999
Delta II 7925-9.5 [61] CCAFS, SLC-17A IIR 3 46 11 D5 On orbit spare
10 November 2020 [33] [62]
USA-150 11 May 2000
Delta II 7925-9.5 [63] CCAFS, SLC-17A IIR 4 51 20 E4 Operational [33]
USA-151 16 July 2000
Delta II 7925-9.5 [64] CCAFS, SLC-17A IIR 5 44 28 B3 Operational [33]
USA-154 10 November 2000
Delta II 7925-9.5 [65] CCAFS, SLC-17A IIR 6 41 14 F5 Retired
9 July 2020 [66]
USA-156 30 January 2001
Delta II 7925-9.5 [67] CCAFS, SLC-17A IIR 7 54 18 E4 On orbit spare
5 March 2018 [68] [69]
USA-166 29 January 2003
Delta II 7925-9.5 [70] CCAFS, SLC-17B IIR 8 56 16 B1 Operational [33]
USA-168 31 March 2003
Delta II 7925-9.5 [71] CCAFS, SLC-17A IIR 9 45 21 D3 Operational [33]
USA-175 21 December 2003
Delta II 7925-9.5 [72] CCAFS, SLC-17A IIR 10 47 22 E6 Operational [33]
USA-177 20 March 2004
Delta II 7925-9.5 [73] CCAFS, SLC-17B IIR 11 59 19 C5 Operational [33]
USA-178 23 June 2004
Delta II 7925-9.5 [74] CCAFS, SLC-17B IIR 12 60 23 F4 Retired
2 March 2020 [75] [33]
USA-180 6 November 2004
Delta II 7925-9.5 [76] CCAFS, SLC-17B IIR 13 61 02 D1 Operational [33]
USA-183 26 September 2005
Delta II 7925-9.5 [77] CCAFS, SLC-17A IIRM 1 53 17 C4 Operational [33]
Also known as IIR-14 first to broadcast L2C signal.
USA-190 25 September 2006
Delta II 7925-9.5 [78] CCAFS, SLC-17A IIRM 2 52 31 A2 Operational [33]
Also known as IIR-15 first satellite to complete a fully operational 32-satellite constellation.
USA-192 17 November 2006
Delta II 7925-9.5 [79] CCAFS, SLC-17A IIRM 3 58 12 B4 Operational [33]
Also known as IIR-16.
USA-196 17 October 2007
Delta II 7925-9.5 [80] CCAFS, SLC-17A IIRM 4 55 15 F2 Operational [33]
Also known as IIR-17.
USA-199 20 December 2007
Delta II 7925-9.5 [81] CCAFS, SLC-17A IIRM 5 57 29 C1 Operational [33]
Also known as IIR-18.
USA-201 15 March 2008
Delta II 7925-9.5 [82] CCAFS, SLC-17A IIRM 6 48 07 A4 Operational [33]
Also known as IIR-19.
USA-203 24 March 2009
Delta II 7925-9.5 [83] CCAFS, SLC-17A IIRM 7 49 01
B6 In Reserve
Also known as IIR-20 broadcasts demonstration L5 signal. Never entered service due to poor quality signal decommissioned on 6 May 2011 but subsequently reactivated for testing. Broadcast PRN-01 before decommissioning, PRN-27 after reactivation. Shifted to PRN-30 as of 8 May 2013 and to PRN-06 as of 3 April 2014. Currently not assigned a PRN. [33]
USA-206 17 August 2009
Delta II 7925-9.5 CCAFS, SLC-17A IIRM 8 50 05 E3 Operational [33]
Originally scheduled for launch in 1999 as IIR-3 but damaged during processing. [84] Also known as IIR-21 L5 services disconnected from J2 port before launch. Final Delta II launch with a United States Air Force payload. [85] Final launch from SLC-17A, final Delta II 7925.
USA-213 28 May 2010
Delta IV M+ (4,2) CCAFS, SLC-37B IIF 1 62 25 B2 Operational [33]
First to broadcast operational L5 signal.
USA-232 16 July 2011
Delta IV M+(4,2) CCAFS, SLC-37B IIF 2 63 01 D2 Operational [33]
USA-239 4 October 2012
Delta IV M+(4,2) CCAFS, SLC-37B IIF 3 65 24 A1 Operational [33]
USA-242 15 May 2013
Atlas V 401 CCAFS, SLC-41 IIF 4 66 27 C2 Operational [33]
USA-248 21 February 2014
Delta IV M+ (4,2) CCAFS, SLC-37B IIF 5 64 30 A3 Operational [33]
USA-251 17 May 2014
Delta IV M+ (4,2) CCAFS, SLC-37B IIF 6 67 06 D4 Operational [33]
USA-256 2 August 2014
Atlas V 401 CCAFS, SLC-41 IIF 7 68 09 F3 Operational [33]
USA-258 29 October 2014
Atlas V 401 CCAFS, SLC-41 IIF 8 69 03 E1 Operational [33]
USA-260 25 March 2015
Delta IV M+ (4,2) CCAFS, SLC-37B IIF 9 71 26 B5 Operational [33]
USA-262 15 July 2015
Atlas V 401 CCAFS, SLC-41 IIF 10 72 08 C3 Operational [33]
USA-265 31 October 2015
Atlas V 401 CCAFS, SLC-41 IIF 11 73 10 E2 Operational [86]
USA-266 5 February 2016
Atlas V 401 CCAFS, SLC-41 IIF 12 70 32 F1 Operational [87]
Vespucci [88]
23 December 2018
Falcon 9 Block 5 CCAFS, SLC-40 III 1 74 04 F4 Operational [89]
Physically occupies the F4 slot but is designated "A6" in the GPS Operational Advisory for control station purposes. [33]
22 August 2019
Delta IV M+ (4,2) CCAFS, SLC-37B III 2 75 18 D6 Operational [90]
Matthew Henson
30 June 2020
Falcon 9 Block 5 CCAFS, SLC-40 III 3 76 23 E5 Operational [91]
The third GPS Block III satellite was initially nicknamed Columbus, but was renamed Matthew Henson before the launch but not widely announced. [92] [93]
5 November 2020
Falcon 9 Block 5 CCAFS, SLC-40 III 4 77 14 B6 Operational [94]

Satellites by block Edit

Block Launched Operational Testing/
Unhealthy Retired Launch
Manufacturer Remarks
Block I 11 0 0 0 10 1 Rockwell International
Block II 9 0 0 0 9 0 Rockwell International One prototype was never launched
Block IIA 19 0 0 0 19 0 Rockwell International
Block IIR 13 8 2 0 2 1 Lockheed Martin
Block IIRM 8 7 1 0 0 0 Lockheed Martin
Block IIF 12 12 0 0 0 0 Boeing
Block III 5 4 1 0 0 0 Lockheed Martin
Block IIIF 0 0 0 0 0 0 Lockheed Martin
Total 77 31 4 0 40 2

Orbital slots (by SVN) Edit

Refer to GPS Constellation Status for the most up-to-date information.

As of 11 December 2020 [update]
Slot Plane
1 65 56 57 61 69 70
2 52 62 66 63 73 55
3 64 44 72 45 50 68
4 48 58 53 67 51 74
5 71 59 76
6 77 75 47 43

Numbers in parentheses refer to non-operational satellites.

Once launched, GPS satellites do not change their plane assignment but slot assignments are somewhat arbitrary and are subject to change.

Cross reference of PRNs to satellite blocks Edit

The following table is for the purpose of making it possible to determine the block associated with a PRN by looking at one column in one table rather than having to search through all rows of three tables. Thus this table can be used to quickly and easily determine the number of satellites in orbit and health associated with each block.

Cross reference of PRNs to blocks
PRN 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 NA

  • H – In orbit and healthy
  • R – Placed in reserve
  • U – Unhealthy and unusable
  • D – Decommissioned
  • T – Launched and undergoing testing

PRN to SVN history Edit

This section is for the purpose of making it possible to determine the PRN associated with a SVN at a particular epoch. For example, SVN 049 had been assigned PRNs 01, 24, 27, and 30 at different times of its lifespan, whereas PRN 01 had been assigned to SVNs 032, 037, 049, 035, and 063 at different epochs. This information can be found in the IGS ANTEX file, which uses the convention "GNN" and "GNNN" for PRNs and SVNs, respectively. For example, SVN 049 is described as:

whereas for PRN 01 the following excerpt is relevant:

A table extracted out of the ANTEX file is made available by the Bernese GNSS Software.

Northrop Grumman and Intelsat Make History with Docking of Second Mission Extension Vehicle to Extend Life of Satellite

DULLES, Va. &ndash April 12, 2021 &ndash Northrop Grumman Corporation (NYSE: NOC) and the company&rsquos wholly-owned subsidiary, SpaceLogistics LLC, have successfully completed the docking of the Mission Extension Vehicle-2 (MEV-2) to the Intelsat 10-02 (IS-10-02) commercial communications satellite to deliver life-extension services. The docking was completed at 1:34 p.m. EDT.

Northrop Grumman is the only provider of flight-proven life extension services for satellites, and this is the second time the company has docked two commercial spacecraft in orbit. The company&rsquos MEV-1 made history when it successfully docked to the Intelsat 901 (IS-901) satellite in February 2020. Unlike MEV-1, which docked above the GEO orbit before moving IS-901 back into service, MEV-2 docked with IS-10-02 directly in its operational GEO orbital location.

&ldquoToday&rsquos successful docking of our second Mission Extension Vehicle further demonstrates the reliability, safety and utility of in-space logistics,&rdquo said Tom Wilson, vice president, strategic space systems, Northrop Grumman and president, SpaceLogistics LLC. &ldquoThe success of this mission paves the way for our second generation of servicing satellites and robotics, offering flexibility and resiliency for both commercial and government satellite operators, which can enable entirely new classes of missions.&rdquo

Under the terms of Intelsat&rsquos satellite life-extension servicing contract, MEV-2 will provide five years of service to IS-10-02 before undocking and moving on to provide services for a new mission.

&ldquoIntelsat has pioneered innovations in space-based technology for more than five decades. We are proud to work side by side with Northrop Grumman on today&rsquos groundbreaking mission, the first-ever docking of a communications satellite in GEO orbit,&rdquo said Intelsat Chief Services Officer Mike DeMarco. &ldquoSpace servicing is a valuable tool for Intelsat in extending the high-quality service experience that our customers depend upon. Northrop Grumman&rsquos MEV technology has helped us extend the life of two otherwise healthy and high-performing satellites, while focusing our innovation capital on advancing the Intelsat next-generation network &ndash this technology is a &lsquowin-win&rsquo for us.&rdquo

The Mission Extension Vehicle is the first in Northrop Grumman&rsquos lineup of satellite servicing vehicles, but following last year&rsquos robotic servicing mission award from DARPA, the company is working with the agency on a mission that will feature the first-ever commercial robotic servicing spacecraft. This mission will expand the market for satellite servicing of both commercial and government client satellites with advanced robotics using the company&rsquos Mission Robotic Vehicle (MRV) to conduct in-orbit repair, augmentation, assembly, detailed inspection and relocation of client satellites through robotics.

To further complement its on-orbit servicing portfolio, Northrop Grumman is leveraging model based systems engineering to develop its Mission Extension Pods (MEPs) which will also provide critical life extension services to aging satellites. The MRV will be used to install these pods on existing in-orbit commercial and government client satellites to extend their mission lives. The company is targeting 2024 for launch of both the MRV and the initial MEPs.

B-roll and animation footage for the mission can be found here. Photos for the mission can be found here.

About Intelsat

As the foundational architects of satellite technology, Intelsat operates the world&rsquos largest and most advanced satellite fleet and connectivity infrastructure. We apply our unparalleled expertise and global scale to connect people, businesses, and communities, no matter how difficult the challenge. Intelsat is uniquely positioned to help our customers turn possibilities into reality &ndash transformation happens when businesses, governments, and communities use Intelsat&rsquos next-generation global network and managed services to build their connected future.

About Northrop Grumman

Northrop Grumman solves the toughest problems in space, aeronautics, defense and cyberspace to meet the ever evolving needs of our customers worldwide. Our 97,000 employees define possible every day using science, technology and engineering to create and deliver advanced systems, products and services.

Satellite communication

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Satellite communication, in telecommunications, the use of artificial satellites to provide communication links between various points on Earth. Satellite communications play a vital role in the global telecommunications system. Approximately 2,000 artificial satellites orbiting Earth relay analog and digital signals carrying voice, video, and data to and from one or many locations worldwide.

Satellite communication has two main components: the ground segment, which consists of fixed or mobile transmission, reception, and ancillary equipment, and the space segment, which primarily is the satellite itself. A typical satellite link involves the transmission or uplinking of a signal from an Earth station to a satellite. The satellite then receives and amplifies the signal and retransmits it back to Earth, where it is received and reamplified by Earth stations and terminals. Satellite receivers on the ground include direct-to-home (DTH) satellite equipment, mobile reception equipment in aircraft, satellite telephones, and handheld devices.

A brief history of GPS

It all started with Sputnik. What seemed at the time like a major defeat in the Cold War, turned out to be the catalyst for one of the most important technologies of the 20th century, and maybe the 21st.

It was October 4th, 1957. Scientists at MIT noticed that the frequency of the radio signals transmitted by the small Russian satellite increased as it approached and decreased as it moved away. This was caused by the Doppler Effect, the same thing that makes the timbre of a car horn change as the car rushes by.

The Russians launched the Sputnik satellite in 1957, surprising the world.

This gave the scientists a grand idea. Satellites could be tracked from the ground by measuring the frequency of the radio signals they emitted, and conversely, the locations of receivers on the ground could be tracked by their distance from the satellites. That, in a nutshell, is the conceptual foundation of modern GPS. That GPS receiver in your phone or on the dash of your car learns its location, rate of speed, and elevation by measuring the time it takes to receive radio signals from four or more satellites floating overhead.

GPS has come a long way since Sputnik. Here are the major milestones along the way.

Currently, a total of 31 GPS satellites orbit the earth twice a day.

1959 The Navy built the first real satellite navigation system, which it called TRANSIT. The system was designed to locate submarines, and started out with six satellites and eventually grew to ten. The subs often had to wait hours to receive signals from the satellites, but the model set the stage for true GPS with continuous signaling from satellites in space.

1963 The Aerospace Corporation completed a study for the military that proposes a system of space satellites that sends signals continuously to receivers on the ground and could locate vehicles moving rapidly across the earth’s surface or in the air. The study lays out the GPS concept that we know today for the first time: receivers in vehicles on the ground would derive a precise set of location coordinates by measuring the transmission times of radio signals from satellites.

The Air Force launched the first "Block I" GPS satellite into space in 1974.

1974 The branches of the military, after having worked on a GPS system for the past 11 years, launch the first satellite of a proposed 24-satellite GPS system called NAVSTAR. The satellite, and many to follow, are meant to test the NAVSTAR concept.

1978-1985 The military launches 11 more test satellites into space to test the NAVSTAR system, which by then was called simply "the GPS System". The satellites carried atomic clocks with them, to more precisely measure transmission times. Some of these satellites (starting in 1980) carried sensors designed to detect the launch or detonation of nuclear devices.

1983 Shortly after the Russians shot down Korean Air flight 007 after it wandered off course into Soviet airspace over the Kamchatka Peninsula, president Reagan offered to let all civilian commercial aircraft use the GPS system (once it was completed) to improve navigation and air safety.

1985 The government contracts with private companies to develop “airborne, shipboard and man-pack (portable)” GPS receivers.

1989 After years of testing, the Air Force finally launches the first fully operational GPS satellite into space. The Air Force had planned to launch the satellite on the Space Shuttle, but changed its plans after the Challenger disaster in 1986 and used a Delta II rocket instead.

1989 Magellan Corporation claims to be the first to market in the U.S. with a hand-held navigation device, the Magellan NAV 1000.

1990 Fearing military adversaries might use the GPS system to advantage, the Defense Department decides to deliberately decrease the accuracy of the system.

1994 The FAA and Bill Clinton tell the worldwide airline industry that can continue using the GPS system free of charge “for the foreseeable future.”

1995 The first rev of the GPS system was finally completed in 1995 when the last of a full “constellation” of 27 fully operational GPS satellites is launched into space. Of those 27, three were used as spares to quickly replace any of the 24 active satellites that failed. The satellites, which weighed between three- and four-thousand pounds, circled the globe twice a day. They were situated so that at least four of them were visible from any place on earth at any time of day.

1998 Vice President Al Gore announced a plan to make the GPS satellites transmit two additional signals to be used for civilian (non-military) applications, especially to improve aircraft safety. Congress approved the plan (called “GPS III”) in 2000.

The Befefon Esc! was the first mobile phone with GPS built in.

1999 Mobile phone manufacturer Benefon launched the first commercially-available GPS phone, a safety phone called the Benefon Esc! The GSM phone was sold mainly in Europe, but many other GPS-enabled mobile phones would follow.

2000 The Defense Department ended the purposeful degradation of GPS, which it implemented before the first Gulf War. GPS became ten times more accurate overnight, and all kinds of industries--from fishing to forestry to freight management--soon began using it.

/>Personal GPS devices like the TomTom Start 45 car navigation device became hugely popular shortly after the turn of the century.

2001As GPS receiver technology got much smaller and cheaper, private companies began pumping out personal GPS products, like the in-car navigation devices from Tom Tom and Garvin.

2004 Qualcomm said it had developed and tested “assisted GPS” technology allowing phones to use cellular signal in combination with GPS signal to locate the user to within feet of their actual location.

The first "Block II" satellite joined the GPS constellation in 2005.

2005 The first of a new generation of GPS satellite, called “Block II,” was launched from Cape Canaveral. The new breed of satellite transmitted signals on a second, dedicated civilian channel.

2009 The Government Accountability Office (GAO) issued a report warning that the $5.8 billion effort to upgrade the GPS satellites was so fraught with technical problems, cost overruns, and delays that some of the satellites could begin to fail in 2010. This sent the Air Force scrambling to allay fears, saying "There's only a small risk we will not continue to exceed our performance standard."

The next generation of GPS satellite, called "Block III" will be activated starting in 2014.

2010-2011 The Air Force launched two new GPS satellites, one in 2010 and one in 2011, that are meant to keep the constellation operable until the next generation “Block III” satellites can begin launching in 2014. The new Block III satellites will add an additional civilian GPS signal, and will enhance the performance of existing GPS service.

2012 At present, the Air Force manages a constellation of 31 operational GPS satellites, plus three decommissioned satellites that can be reactivated if needed. The constellation is managed to ensure the availability of at least 24 GPS satellites, 95% of the time. On October 4 the Air Force will launch the next addition to the constellation, the GPS IIF-3 satellite, into space.

Sources: The Rand Corporation, United States Naval Observatory, United Launch Alliance,

This story, "A brief history of GPS" was originally published by TechHive .

Mark has been writing about networks - social and wireless - since 2005. Independent and outgoing, he enjoys travelling, wine, and skiing. His favorite book is "Atlas Shrugged" by Ayn Rand.

Satellite data suggests coronavirus may have hit China earlier: Researchers

Researchers say surge in cars at hospitals may indicate outbreak in fall.

Counting cars: Satellite images suggest coronavirus may have hit China last fall

Dramatic spikes in auto traffic around major hospitals in Wuhan last fall suggest the novel coronavirus may have been present and spreading through central China long before the outbreak was first reported to the world, according to a new Harvard Medical School study.

Using techniques similar to those employed by intelligence agencies, the research team behind the study analyzed commercial satellite imagery and "observed a dramatic increase in hospital traffic outside five major Wuhan hospitals beginning late summer and early fall 2019," according to Dr. John Brownstein, the Harvard Medical professor who led the research.

Brownstein, an ABC News contributor, said the traffic increase also "coincided with" elevated queries on a Chinese internet search for "certain symptoms that would later be determined as closely associated with the novel coronavirus."

Though Brownstein acknowledged the evidence is circumstantial, he said the study makes for an important new data point in the mystery of COVID-19's origins.

“Something was happening in October,” said Brownstein, the chief innovation officer at Boston Children’s Hospital and director of the medical center’s Computational Epidemiology Lab. “Clearly, there was some level of social disruption taking place well before what was previously identified as the start of the novel coronavirus pandemic.”

Since the outbreak in China last year, the coronavirus has swept across the globe infecting nearly 7 million and killing more than 400,000 worldwide, according to a count by Johns Hopkins University. It is believed that the virus jumped from animal species, where it had little effect, to humans, where it has become the most potent natural killer since the Spanish flu pandemic a century ago.

Though Chinese officials would not formally notify the World Health Organization until Dec. 31 that a new respiratory pathogen was coursing through Wuhan, U.S. intelligence caught wind of a problem as early as late November and notified the Pentagon, according to four sources briefed on the confidential information.

Because the origin of a novel virus is so hard to pin down but so critically important for scientists to understand, experts around the world are racing to uncover the secrets of the pathogen formally known as SARS-CoV2. The task for researchers is made far more complicated by the Chinese government’s refusal to fully cooperate with Western and international health authorities, American and WHO officials have said.

Brownstein and his team, which included researchers from Boston University and Boston Children’s Hospital, have spent more than a month trying to pin down the signs for when the population of Hubei province in China first started to be stricken.

The logic of Brownstein’s research project was straightforward: respiratory diseases lead to very specific types of behavior in communities where they’re spreading. So, pictures that show those patterns of behavior could help explain what was happening even if the people who were sickened did not realize the broader problem at the time.

“What we're trying to do is look at the activity, how busy a hospital is,” Brownstein said. “And the way we do that is by counting the cars that are at that hospital. Parking lots will get full as a hospital gets busy. So more cars in a hospital, the hospital's busier, likely because something's happening in the community, an infection is growing and people have to see a doctor. So you see the increases in the hospital business through the cars… We saw this across multiple institutions.”

The picture painted by the data is not in itself conclusive, Brownstein acknowledged, but he said the numbers are telling.

“This is all about a growing body of information pointing to something taking place in Wuhan at the time,” Brownstein said. “Many studies are still needed to fully uncover what took place and for people to really learn about how these disease outbreaks unfold and emerge in populations. So this is just another point of evidence.”

Disease ecologist Peter Daszak, president of the nonprofit EcoHealth Alliance in Manhattan, said the Harvard study “is absolutely fascinating."

“You need to look at every possible bit of evidence, where it came from and when it emerged,” said Daszak, whose organization works to understand the origin of emerging diseases. “When we do analysis after outbreaks, we find that the diseases had been in circulation days, weeks, months, years before. I really believe that’s what we’re going to find with COVID-19.”

David Perlin, chief science officer at the Center for Discovery and Innovation in New Jersey, said he was intrigued by Brownstein’s research, though he wasn’t totally convinced.

“I think some of the methods are questionable and their interpretation is slightly over-interpreted,” Perlin said. “The problem is we only have a subset of data here. I always worry when people start drawing inferences from data subsets, cherry-picking data [like the internet searches]. It’s suggestive."

Photographs taken from space suggests a crisis below

Starting with nearly 350 images captured by private satellites circling the globe, Brownstein’s study first examined traffic and parking outside major hospitals in Wuhan for the past two years. Among them were photographs snapped from space approximately every week or every other week through the fall of 2019. From the approximately 350 frames, researchers found 108 usable images, showing locations without obstruction from smog, tall buildings, clouds or other features that could complicate satellite analysis.

“It has to be right at noon,” Brownstein said, “because you basically want direct sunlight. You don’t want shadows to prevent our ability to count the cars.”

On Oct. 10, 2018, there were 171 cars in the parking lot of Wuhan’s Tianyou Hospital, one of the city’s largest. A year later, satellites recorded 285 cars -- a 67% increase, according to the data reviewed by the researchers and shared with ABC News.

Other hospitals showed up to a 90% increase when comparing traffic between fall of 2018 and 2019, according to the study. At Wuhan Tongji Medical University, the spike in car traffic was found to have occurred in mid-September 2019.

To ensure they were not reaching faulty conclusions, researchers said they took into account everything that could explain away traffic surges -- from large public gatherings to the possibility of new construction at the hospitals. Still, they said they found statistically significant increases in the numbers of cars present.

“If you look at all of the images, observations we've ever had of all of these locations since 2018, almost all of the highest car counts are all in the September through December 2019 time frame,” said Tom Diamond, president of RS Metrics, which worked with the Brownstein research team.

As an initial "validation" of their methodology of extrapolating information about movement through the review of satellite images, researchers said they compared parking lot activity at the Huanan Seafood Market in mid-September, when the market was busy, and after the market was shut down by authorities after reports emerged that the wet market may have been ground zero for the novel coronavirus outbreak. They said they found a marked change. “The images validate the concept that activity and movement is shown through the lens of these sort of parking lots,” said Brownstein.

The study has been submitted to the journal Nature Digital Medicine and is under peer review. It is scheduled to be posted Monday morning on “Dash,” Harvard’s preprint server for medical papers.

On Monday morning the website for "Dash" suffered a temporary outage. A spokesperson for Harvard Medical School told ABC News they were investigating the incident.

In conducting the project, RS Metrics, an intelligence-analysis firm that analyzes satellite imagery for corporate clients, employed techniques designed to identify and monitor changes in the patterns of life and business.

It’s similar to work done by analysts at the Central Intelligence Agency and the Defense Intelligence Agency, who pore over images each day to try to figure out what is happening on the ground – especially in places where governments restrict the flow of people and news.

Diamond told ABC News the Wuhan region was clearly experiencing a widespread health problem in the months before China’s government acknowledged publicly that a contagion was coursing through the densely populated city. That announcement came on New Year’s Eve when the Wuhan Municipal Health Commission, China reported a “cluster” of pneumonia cases in its city.

“At all the larger hospitals in Wuhan, we measured the highest traffic we’ve seen in over two years during the September through December 2019 time frame,” Diamond said. “Our company is used to measuring tiny changes, like 2% to 3% growth in a Cabella’s or Wal-Mart parking lot. That was not the case here. Here, there is a very clear trend.”

Former acting Homeland Security Undersecretary John Cohen, who oversaw DHS intelligence operations during the Obama administration, said the new research suggests that COVID-19, which has already killed more than 110,000 Americans, was likely brought to the U.S. by travelers from Wuhan long before it was detected.

“This study raises serious questions about whether the coronavirus was first introduced into the United States earlier than previously reported and whether measures announced in late January restricting travel from China were too little too late,” said Cohen, now an ABC News contributor.

Satellite images suggesting a change in life patterns in Wuhan were also a key factor in classified early U.S. intelligence reporting.

In April, ABC News reported that the National Center for Medical Intelligence (NCMI) received word in late November that a contagion was sweeping through Wuhan, changing the patterns of life and business and posing a threat to the population. Sources familiar with the reports said NCMI, a component of the military’s Defense Intelligence Agency, based the analysis on wire and computer intercepts coupled with satellite images similar to those used by Brownstein’s team.

After that story was broadcast, the NCMI’s director issued a statement, denying that a formal “product/assessment” was generated in November. The statement did not address preliminary intelligence reports. When contacted Friday with the results of the new Harvard study, the Pentagon’s chief spokesman, Jonathan Hoffman, said he had “nothing to add.”

The Office of the Director of National Intelligence declined to comment.

In response to questions about the new Harvard Medical study, the State Department Sunday again criticized the government in Beijing for withholding from the world community critical public health information.

“The Chinese government's cover up of initial reporting on the virus is just one more example of the challenges presented by the Chinese Communist Party's hostility toward transparency,” a State Department spokesperson told ABC News. “The Chinese government has a responsibility to share information on the virus and support countries as the world responds to COVID-19.”

In March, the Hong Kong-based South China Morning Post newspaper, citing Chinese government data, reported that the first case of COVID-19 could be traced back to November 17, 2019. In recent days, Chinese health officials have told local media that the virus likely was spreading before they realized, though they have offered no details.

ABC News sought comment on the new study from the hospitals in Wuhan that were analyzed, the local public health agency and the Chinese embassy in Washington. The only response received by the network came from the Chinese embassy, where officials pointed to a white paper released Sunday the China State Council.

“The novel coronavirus is a previously unknown virus,” the report documents. “Determining its origin is a scientific issue that requires research by scientists and doctors. The conclusion must be based on facts and evidence.”

The council also defended the Chinese government’s response, writing, “China has also acted with a keen sense of responsibility to humanity, its people, posterity, and the international community.”

Tuesday a spokesperson for the Chinese Foreign Ministry told reporters she had not seen the Harvard study, but thought it was "ridiculous to come to this kind of conclusion based on superficial [observations], such as traffic volumes. It is incredibly ridiculous."

The spokesperson, Hua Chunying, said she was not a scientist, but found the conclusions "very far-fetched" and more generally urged the U.S. and China to work together on combating what she called false information.

On the ground, internet searches for symptoms associated with COVID

Brownstein said he and his researchers found the hospital-traffic data to be even more compelling after digging into internet search patterns. Around the time the hospital traffic was surging, there was a spike in online traffic in the Wuhan region among users asking China’s Baidu search engine for information on “cough” and “diarrhea.”

“While queries of the respiratory symptom ‘cough’ show seasonal fluctuations coinciding with yearly influenza seasons, ‘diarrhea’ is a more COVID-19-specific symptom and only shows an association with the current epidemic,” according to the study. “The increase of both signals precede the documented start of the COVID-19 pandemic in December.”


Heatwave Scorches the Middle East

A phenomenon known as a &ldquoheat dome&rdquo set the stage for remarkably high temperatures as meteorological summer got under way.

Snow Cover

Snow and ice influence climate by reflecting sunlight back into space. When it melts, snow is a source of water for drinking and vegetation too much snowmelt can lead to floods. These maps show average snow cover by month.

Sea Surface Temperature

Ocean temperatures can influence weather, such as hurricane formation, and climate patterns, such as El Niño. These maps show the temperature at the surface of the world&rsquos seas and oceans.

Sea Surface Temperature Anomaly

These maps depict how much hotter or cooler an ocean basin was compared to the long-term average. Temperature anomalies can indicate changes in ocean circulation or the arrival of patterns like El Niño and La Niña.

Western Soils and Plants are Parched

For the second year in a row, drought has overtaken much of the United States from the Rocky Mountains to the Pacific Coast.


Greenness is an important indicator of health for forests, grasslands, and farms. The greenness of a landscape, or vegetation index, depends on the number and type of plants, how leafy they are, and how healthy they are.

Satellite Observes Ship Fire Off Sri Lanka

NASA plays a role in providing observations and analysis of natural and technological disasters.

Lake Victoria&rsquos Rising Waters

Intense rains during the wet season for a second year in a row have caused trouble for riparian communities near Africa&rsquos largest lake.

Aerosol Size

Sea salt, volcanic ash, dust, wildfire smoke, and industrial pollution are types of airborne aerosols. Natural aerosols tend to be larger than human-made aerosols. These maps show when and where aerosols come from nature, humans, or both.

Dual Storms in the Andes Mountains

A rare winter-like storm struck central Chile and Argentina in the middle of austral summer, with drastically different consequences compared to a typical winter storm.

Mission: Biomes

Have you ever wondered what it would be like to live in a different part of the world? What would the weather be like? What kinds of animals would you see? Which plants live there? By investigating these questions, you are learning about biomes.

Africa Sheds Some Dust

The millions of tons of dust lofted out of Africa each year are a visual reminder of how Earth&rsquos systems are interconnected.

How to Interpret a Satellite Image: Five Tips and Strategies

What do you do when presented with a new satellite image? Here's what the Earth Observatory team does to understand the view.

Cloud Fraction

In addition to making rain and snow, clouds can have a warming or cooling influence depending on their altitude, type, and when they form. These maps show what fraction of an area was cloudy each month.

Early or Late Spring Blooms? Both Affect Asthma

Recent research shows that changes in the onset of spring—both early and late—can lead to more severe asthma for some people.

Published Jun 3, 2021 in Earth Matters

Blue Marble Next Generation

12 months of high-resolution global true color satellite imagery.

A Celebration of Clouds: From Space, Earth Has an Elegant Atmosphere

Clouds can be a nuisance when scientists are trying to observe features on Earth's surface. But at other times, clouds are exactly what they want to see. These images highlight some of the more unusual and beautiful clouds observed in recent years from space.

Earth &mdash A Photo-Essay

NASA has a unique vantage point for observing the beauty and wonder of Earth and for making sense of it. The images in this book tell a story of a 4.5-billion-year-old planet where there is always something new to see.

Tournament Earth: Astronaut Photography

Click to see the 2021 champion.

Earth at Night

Satellite images of Earth at night have been a curiosity for the public and a tool of fundamental research for at least 25 years. They have provided a broad, beautiful picture, showing how humans have shaped the planet and lit up the darkness.

Picturing Earth: Astronaut Photography In Focus

For 20 years, astronauts have been shooting photos of Earth from the space station. Like everything the astronauts do, they are trained for this job. And like everything they do, there is purpose and intention behind it.

Picturing Earth: Behind the Scenes

From their perch on the space station, astronauts have spent 20 years sharing a story about Earth as they see it from above. Like the directors of a film, those astronaut storytellers have a crew working behind the scenes to help them tell the story. Meet the Earth Science and Remote Sensing Unit.

How Satellite Radio Works

We all have our favorite radio stations that we preset into our car radios, flipping between them as we drive to and from work, on errands and around town. But when you travel too far away from the station, the signal breaks up and fades into static. Most radio signals can only travel about 30 or 40 miles (48 to 64 kilometers) from their source. On long trips, you might have to change radio stations every hour or so as the signals fade in and out. And it's not much fun scanning through static trying to find something -- anything -- to listen to.

Now, imagine a radio station that can broadcast its signal from more than 22,000 miles (35,000 kilometers) away and then come through on your car radio with complete clarity. You could drive from Tacoma, Wash., to Washington, D.C., without ever having to change the radio station! Not only would you never hear static interfering with your favorite tunes, but the music would be interrupted by few or no commercials.

XM Satellite Radio and Sirius Satellite Radio each launched such a service at the beginning of the 21st century. Satellite radio, also called digital radio, offers uninterrupted, near CD-quality music beamed to your radio from space.

In February 2007, XM Satellite Radio and Sirius Satellite Radio announced their plans to merge into a single company. XM and Sirius were both in debt, and believed a merger would quickly solve that problem. They thought that the merger would also lead to lower prices and more programming choices for consumers. Some people were skeptical about the two companies joining, though, fearing a monopoly would only reduce competition, raise prices and affect consumers poorly. Sirius and XM received approval from the U.S. Department of Justice, but the companies couldn't move until the FCC begrudgingly allowed the merger to go forward in July 2008. The new company goes by the name Sirius XM Radio.

­ Even though XM and Sirius had financial trouble, satellite radio still has a fairly strong fan base. The new Sirius XM company has more than 18 million subscribers [source: Sirius XM]. ­Car manufacturers have been installing satellite radio receivers in some models for a few years now, and several portable satellite radio receivers are available from a variety of electronics companies. In this article, you'll learn what separates satellite radio from conventional radio and about the equipment you'll need to pick up satellite radio signals. ­

Satellite radio is an idea over a decade in the making. In 1992, the U.S. Federal Communications Commission (FCC) allocated a spectrum in the "S" band (2.3 GHz) for nationwide broadcasting of satellite-based Digital Audio Radio Service (DARS). Only four companies applied for a license to broadcast over that band. The FCC gave licenses to two of these companies in 1997. CD Radio (later Sirius Satellite Radio) and American Mobile Radio (later XM Satellite Radio) paid more than $80 million each to use space in the S-band for digital satellite transmission.

At this time, there are two space-based radio broadcasters:

­ Satellite radio companies are comparing the significance of their service to the impact that cable TV had on television 30 years ago. Listeners aren't able to pick up local stations using satellite radio services, but they have access to hundreds of stations offering a variety of music genres. Each company has a different plan for its broadcasting system, but the systems do share similarities. Here are the key components of the two satellite radio systems:

Satellite radio works a lot like satellite TV -- you purchase a receiver and pay a monthly subscription fee for a certain number of channels. For the moment, there are slight variances in the three satellite radio companies' systems. In the next three sections, we will profile each of the companies and their current satellite radio services.

XM and Sirius each offered more than 100 channels. Although the companies merged, both XM and Sirius still exist as separate services. Subscribers to one services can purchase an additional "best of" subscription to the other service. The pricing is the same under each plan: $16.99 per month for the full plan plus the "best of" option for the other service.

While XM Radio and Sirius have merged into a single company, the two services aren't fully integrated yet. Part of the reason for this is due to differences in hardware and software.

XM Radio uses two Boeing HS 702 satellites, appropriately nicknamed "Rock" and "Roll," and two BSS 702 satellites it calls "Rhythm" and "Blues," placed in parallel geostationary orbit, two at 85 degrees west longitude and the other two at 115 degrees west longitude. Geostationary Earth orbit (GEO) is about 22,223 miles (35,764 km) above Earth, and is the type of orbit most commonly used for communications satellites. The first XM satellite, "Rock," was launched on March 18, 2001, with "Roll" following on May 8 of the same year. A design flaw in the HS 702 satellite caused its solar panels to function inefficiently. XM launched "Rhythm" on February 28, 2005, and "Blues" on October 30, 2006, to replace the older satellites. Then XM Radio powered down "Rock" and "Roll." The older satellites remain in orbit and can serve as backups, if necessary.

XM Radio's ground station transmits a signal to its two active GEO satellites, which bounce the signals back down to radio receivers on the ground. The radio receivers are programmed to receive and unscramble the digital data signal, which contains more than 170 channels of digital audio. In addition to the encoded sound, the signal contains information about the broadcast. The song title, artist and genre of music are all displayed on the radio. In urban areas, where buildings can block out the satellite signal, XM's broadcasting system is supplemented by ground transmitters.

Each receiver contains a proprietary chipset. XM began delivering chipsets to its XM radio manufacturing partners in October 2000. The chipset consists of two custom integrated circuits designed by STMicroelectronics. XM has partnered with Pioneer, Alpine, Clarion, Delphi Delco, Sony and Motorola to manufacture XM car radios. Each satellite radio receiver uses a small, car-phone-sized antenna to receive the XM signal. General Motors has invested about $100 million in XM, and Honda has also signed an agreement to use XM radios in its vehicles. GM began installing XM satellite radio receivers in selected models in early 2001.

Currently, subscribers can receive the regular XM channel lineup for $12.95 per month. For that price, listeners get more than 170 channels of music, talk and news. They also get access to XM Radio online, a streaming audio service with more than 80 channels. Many of the channels have no commercials, and none of the channels have more than seven minutes of ads per hour. XM's content providers include USA Today, BBC, CNN, Sports Illustrated and The Weather Channel. The service bolsters that lineup with its own music channels.

Sirius originally used three SS/L-1300 satellites, instead of GEO satellites, to form an inclined elliptical satellite constellation. Sirius said the elliptical path of its satellite constellation ensures that each satellite spends about 16 hours a day over the continental United States, with at least one satellite over the country at all times. Sirius completed its three-satellite constellation on Nov. 30, 2000. A fourth satellite will remain on the ground, ready to be launched if any of the three active satellites encounters transmission problems. In 2006, Sirius purchased a GEO satellite because of its superior signal delivery. The GEO satellite will supplement the elliptical satellites, not replace them. It is currently under construction.

The Sirius system is similar to that of XM. Programs are beamed to one of the three Sirius satellites -- the satellites then transmit the signal to the ground, where your radio receiver picks up one of the channels within the signal. Signals are also be beamed to ground repeaters for listeners in urban areas where the satellite signal can be interrupted.

Just like XM Radio, Sirius currently offers its regular subscription for $12.95 per month. Sirius produces car radios and home entertainment systems, as well as car and home kits for portable use. The Sirius receiver includes two parts: the antenna module and the receiver module. The antenna module picks up signals from the ground repeaters or the satellite, amplifies the signal and filters out any interference.­The signal is then passed on to the receiver module. Inside the receiver module is a chipset consisting of eight chips. The chipset converts the signals from 2.3 gigahertz (GHz) to a lower intermediate frequency. Sirius also offers an adapter that allows conventional car radios to receive satellite signals.

In March 2007, Sirius introduced a new service called Sirius Backseat TV. Sirius partnered with several car manufacturers to create a service that broadcasts programming from Nickelodeon, the Cartoon Network and the Disney Channel that televisions with special Sirius receivers can pick up. People riding in the front of the vehicle can still listen to other Sirius radio stations while the kids watch television in the back.

So far, 1worldspace has been the farthest-reaching company in the satellite radio industry. It put two of its three satellites, AfriStar and AsiaStar, in geostationary orbit before either of the other two companies launched one. AfriStar and AsiaStar were launched in October 1998 and March 2000, respectively. AmeriStar, which will offer service to South America and parts of Mexico, has not yet been launched. Each satellite transmits three signal beams, carrying more than 60 channels of programming, to three overlapping coverage areas of about 5.4 million square miles (14 million square kilometers) each. Each of the 1worldspace satellites' three beams can deliver more than 50 channels of crystal-clear audio and multimedia programming via the 1,467- to 1,492-megahertz (MHz) segment of the L-Band spectrum, which is allocated for digital audio broadcasting.

The United States is not currently part of 1worldspace's coverage area, although the company has invested in Sirius XM Radio and has an agreement with the company to share any technological developments. 1worldspace is going beyond one nation and eyeing world domination of the radio market. That might be overstating the company's intent a bit, but 1worldspace does plan to reach the corners of our world that most radio stations can't. There are millions of people living in 1worldspace's projected listening area who can't pick up a signal from a conventional radio station. 1worldspace says it has a potential audience of about 4.6 billion listeners spanning five continents.

1worldspace broadcasters uplink their signal to one of the two operational satellites through a centralized hub site or an individual feeder link station located within the global uplink beam. The satellite then transmits the signal in one, two or all three beams on each satellite. Receivers on the ground then pick up the signal and provide CD-quality sound through a detachable antenna.

1worldspace satellite receivers are capable of receiving data at a rate of 128 kilobits per second (Kbps). The receivers use the proprietary StarMan chipset, manufactured by STMicroelectronics, to receive digital signals from the satellites.

For more information on satellite radio and related topics, check out the links on the next page.