Zarya - Soviet, Russian and International Spaceflight
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Launches and Orbital Operations

Tyneside, UK
2021 Apr 11
Sunday, Day 101

Maintained by:

Mission Events 2021:

Mission Events 2020:



Intelsat 10-02 with MEV-2

track map

The plot is updated in real time as new orbital data becomes available from Space-Track and each point represents one set of data. The plot is drawn for an observer standing on the Earth and looking at the sky so longitude west increases to the right. What follows are notes to explain the plot's evolution.

Orbit details for MEV-2 since launch 2020 Aug 15 can be found in the launch list for 2020.

Apr 7

MEV-2 makes rendezvous with Intelsat.

Apr 4

A thruster firing by Intelsat causes a small westerly drift that starts to move it closer to MEV-2.

Apr 3

MEV-2 continues to trail Intesat 10-02, drifting freely in orbit with no obvious thruster firings.

A small thruster firing by Intelsat results in a slight move eastward and maintains the separation from MEV-2.

Apr 1

MEV-2 trailing Intelsat by 120-125 km when measured along the orbit. It has been that way since Mar 27.

Now 56 days since MEV-2 'arrived' on the scene.

Mar 31

Spacetrack has switched back the IDs so the correct data is coming through against each satellite.

Mar 30

An image made on the evening of Mar 29 by Dr Marco Langbroek (reproduced below with permission) confirms that the most recent IDs as published by Space-Track have indeed been switched round. The image is labelled to match the published orbit data but the brighter object, marked as MEV-2, is actually Intelsat and 'Intelsat' is actually MEV-2.

The plot takes account of the switch. It shows that the most recent manoeuvre by MEV-2 was to move eastwards and away from Intelsat.

NOTE: To reduce confusion, the longitude axis of the plot has been reversed when compared with earlier versions so °west now increases to the right.

Marco image

Mar 29

The two have moved away from each other noticeably. There also exists a possibility that the IDs have become switched round between them.

NOTE: Time from arrival to capture for the MEV-1 mission was 25 days. It is now 53 days since MEV-2 arrived near Intelsat 10-02 and it was conducting close-in operations around the 25 day mark.

Possible Reasons for Not Docking:

Intelsat 10-02 unable to maintain attitude precisely enough to guarantee capture,

Some element of Intelsat 10-02 structure such as loose insulation, or part of the vehicle that did not deploy as expected at launch, blocking the MEV docking/capture mechanism,

MEV-2 unable to maintain attitude precisely,

Electronic problem with MEV-2 impeding proper operation of the approach, rendezvous or docking/capture control system,

Physical problem with operation of MEV-2 docking/capture mechanism,

Some element of MEV-2 not deployed properly and blocking the docking/capture mechanism.

Mar 23

Data from Space-Track shows them with a few kilometres of each other, maybe the start of another period of manoeuvres aimed at MEV-2's capture of its target.

Mar 19

The 28 day cycle exhibited by Intelsat has westerly and easterly peaks, separated from each other by 14 days. The peak dates are when disturbing influences are at a minimum, making the orbit the most stable it can be under natural influences.

Intelsat held itself steady, and the close proximity manoeuvres of MEV-2 occurred, a few days either side of the easterly peak on February 27. The next peak is March 27 so the current 'stand-off' may end in the next 2-3 days as MEV-2 goes for another try.

Mar 18

MEV-2 continues to stand away by about 0.03° longitude.

Intelsat's behaviour mid March is a near-repeat of mid-February. It results from the Moon's gravitational pull, cycling every 28 daya as the Moon completes one orbit around Earth, and demonstrates one of the things that GEO satellite operators have to contend with.

Mar 15

Orbit data from Space-Track resumes after nearly four days hiatus. Shows Intelsat holding near 1°.04 west and MEV near 1°.01 west and also holding steady.

Mar 11

Intelsat 10-02 remains near 1°.03 west, MEV-2 continues to drift slowly eastwards.

Mar 10

As a result of a thruster firing early in the day, Intelsat 10-02 moves itself westwards by about 15 km (to 1°.03 west) and passes within 5 km of MEV-2.

Mar 5

After using its thrusters to move westwards and away from Intelsat, MEV-2 begins a slow move back to the vicinity of its target. Separation at the time is about 50 km with both satellites drifting eastward but converging on each other.

Mar 3

Intelsat ceases to hold station and starts to drift in an easterly direction under gravitational influence. MEV-2 commences a separation manoeuvre and begins to move westward.

Feb 23

MEV-2 is within a few tens of metres of Intelsat and seems to be set up to capture its target. It may have arrived there a few days earlier but Space-Track data was confusing and contradictory in that period.

Feb 18

Intelsat 10-02 begins to use its thrusters to hold station near 1°.015 west ready for close rendezvous with MEV-2.

2021 Feb 4

MEV-2 arrives in the vicinity of Intelsat 2 and begins to shadow it from a few kilometres away.

2020 Aug 15, 22:04 UTC

MEV-2 launched from CSG using Ariane 5.

Page updated as indicated by log entries
Plot updated in real time