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SSETI Express Power Problems

Here is a report that has just been issued by the SSETI Express Project Manager. It gives the latest up-to-date situation regarding the satellite.73Graham++++++++++++++++++++++++++

The SSETI Express student microsatellite mission has been a remarkable success, achieving its two first mission objectives and a number of important milestones. Due to a failure in the electrical power system on board the spacecraft is inoperable and mission control is on "standby". There is a small but significant possibility of recovery, the likelihood of which is being ascertained by ongoing testing. The educational goals of the project continue to be met by the student teams who are still working hard to analyse and understand all available data, such that the lessons learned can be applied to future missions.


Detailed statement:

Despite the brevity of the initial mission a number of important milestones were achieved:

1) Objective 1 is fulfilled: Reaching the launch pad after progressing through the challenging and rigorous acceptance process is a major milestone demonstrating the capability and applicability of the SSETI Programme itself and all of the student teams involved.

2) Objective 2 is fulfilled: All evidence suggests that the three Cubesat passengers were successfully deployed into orbit by SSETI Express, and were hence able to begin their own independent missions. The Cubesats Xi-V and UWE-1 are alive and well, the status of NCube-2 has yet to be confirmed.

3) SSETI Express booted up in orbit and transmitted its first data back to earth precisely on schedule. This data was received and decoded by the primary groundstation and several others. This confirmed that SSETI Express survived its journey into space and was successfully separated from the launcher.

4) The primary groundstation established reliable two-way communication with SSETI Express. This was a remarkable achievement further demonstrating the capability of the SSETI Programme and all the students involved.

5) A significant amount of house-keeping data was downloaded from the spacecraft, allowing for a detailed analysis of the situation on board. This also involved the global network of radio amateurs, who have given us invaluable support and additional data during this mission.


The problem:

6) In order to ensure the safety of the other spacecraft on the same launch vehicle, SSETI Express remained inactive and coasted for 65 minutes before deploying the three Cubesat passengers.

7) During this time all the energy gathered by the solar panels was to be dissipated within the spacecraft. Evidence strongly suggests that this dissipation system failed by fusing on, therefore not allowing any energy to charge the spacecraft batteries.

8) The battery charge steadily declined during the mission, causing the spacecraft to enter safe mode after approximately 6.5 hours, and eventually shutting it down altogether.


The outlook:

9) Careful analysis of the data received, coupled with ground-based computer simulations and hardware tests, strongly support the proposed theory of a specific component failure in the excess power dissipation system.

10) Ground-based hardware tests confirm the possibility of a further failure mode of the specific component, which would allow the batteries to charge and the spacecraft to operate once again.

11) Testing is ongoing to ascertain the specific likelihood of (10), and to investigate other possible alternative explanations.

12) Given that the spacecraft is currently inoperable, the mission cannot continue as planned. It is therefore on indefinite "standby", pending the technical possibility of re-activation of the spacecraft, as in (10).

13) The team remain hopeful and vigilant. The primary groundstation and mission control centre are being configured for autonomous monitoring of the spacecraft, such that if it reactivates the team will be immediately alerted and ready to resume the mission.

14) The educational goals of the mission continue to be met daily as we try to analyse and understand the events since the launch.


Neil Melville - Project Manager
Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
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