Can we re-purpose space assets?

Express-AM4: Total loss or a new purpose?

Paul D. Spudis
The Once and Future Moon
Smithsonian Air & Space
 

The Russians launched a communications satellite, the Astrium Express-AM4, in August 2011.  After a failure in its Proton launch vehicle (resulting in loss of contact and control), it was presumed lost.  However, it survived and is trapped in a high-inclination orbit – a 20,000 by 650 km elliptical orbit (inclined 52° from the equator).  Forcing it to operational geosynchronous (GEO) orbit would take most of its fuel, leaving the satellite with a very limited useful lifetime.  The satellite was insured and payment has been collected on the mishap of the launch but the Russians have yet to decide on what to do with this wayward satellite circling Earth in the “wrong” orbit.  Recently they indicated that there is enough fuel to conduct a controlled re-entry and descent, guiding the satellite to a safe, watery grave somewhere in one of the Earth’s oceans.

Must this be the fate of a newly orbiting space asset?  True, it is in the wrong orbit for its original use as a commercial communications satellite, originally headed for 36,000 km above Earth to GEO, but what if instead it were repurposed?  A company called Polar Broadband has an interesting idea about turning this mishap around and using it for a good purpose.  Though not for its original users, they see a way to use this communication satellite for an assignment it is now suited to do.*  Polar Broadband envisions moving this satellite into an elongate orbit with a 24-hour period and apogee (high point) over its southern extreme (52° S) because a satellite in such an orbit can do service as a communications resource for Antarctica.

Antarctica!?  It’s a remote barren landscape!  True it is remote, but the population of this lonely continent swells greatly during southern summer when hundreds of scientists descend down under to conduct a wide variety of scientific studies.  Although there are a few central bases (like McMurdo), communications with teams in the field can be spotty and unreliable.  If this satellite could be positioned into a new orbit, it would appear in the sky for about 16 hours each day, allowing predictable, reliable communications from a variety of locations in Antarctica, including the difficult to access Amundsen-Scott South Polar Station.

An attempt to repurpose this satellite hardware appears to be a win-win for everybody.  The National Science Foundation gets a new satellite asset for safe and productive communications with and operations in the Antarctic, Polar Broadband gets to sell this service to the NSF, and by giving a green light to this endeavor, the Russians will have benefited the international scientific community.  There are no guarantees but the possibility for these rewards make the attempt worthwhile.

Two of the original 5-vehicle swarm having completed the THEMIS mission were re-purposed to become ARTEMIS, exploring the solar-terrestrial and lunar electro-magnetic plasma environment, arriving in lunar orbit after a long, low energy transfer maneuver by way of LaGrange points in 2011. Now these robust spacecraft are part of an American team totaling five unmanned probes now in orbit around the Moon [NASA].

This experiment also holds relevance for future lunar exploration.  What is being proposed for Express-AM4 is to create a reliable satellite  system so that a distant base can communicate with its mission control for science and operations.  Building and operating a working outpost at one of the lunar poles will require high bandwidth communication to remotely control robotic assets and return volumes of scientific and engineering data to Earth.  Acquiring and gaining operational experience with polar communications is a good analog to doing so around the Moon, where we will require similar communications relays with long dwell times over the poles for access to polar spacecraft and robotic vehicles.

The Russians have said that the satellite has suffered extensive radiation damage as a result of its continued passage through the Van Allen radiation belts.  But in its new guise, the satellite would receive far less radiation exposure than it would by going to GEO.  Put to new use, this “lost” satellite could provide vital communications to and between scientific expeditions and assets in Antarctica and provide us with experience relevant to future operations on the Moon.  A wayward communications satellite has presented us with an unexpected and rich opportunity.

Originally published March 19, 2012 at his Smithsonian Air & Space blogThe Once and Future Moon, Dr. Spudis is a senior staff scientist at the Lunar and Planetary Institute. The opinions expressed are those of the author and are better informed than average.

*Update: Controllers deorbited Astrium Express AM4 on Sunday, March 25, despite the last-minute bid to salvage the spacecraft.

ARTEMIS P1 successfully enters lunar orbit

The predicted path for ARTEMIS P1 as it enters lunar orbit [NASA/Goddard/D. Folta]. Play/Download Animations HERE.

Karen C. Fox
NASA/Goddard

On June 22, ARTEMIS P1 began firing its thrusters to move out of its kidney-shaped "libration" orbit on one side of the moon, where it has been since January. Three successive maneuvers were used to kick the spacecraft out of its orbit and send it on a trajectory toward the moon.

It continued on that path until June 27 at 10:04 a.m. EDT when the spacecraft was about 2,400 miles from the moon. At that point, flight engineers at UC Berkeley issued the first commands to move it into orbit around the moon. Two more maneuvers helped fine-tune the position, and as of 12:30 p.m. EDT, ARTEMIS P1 is now in lunar orbit.

"ARTEMIS is the first mission ever to orbit the moon's Lagrangian points."

This is the culmination of a complex, two-year journey that relied predominantly on gravity boosts and used minimal fuel. The path from its orbit around Earth to the moon was developed and orchestrated by engineers at the NASA's Goddard Space Flight Center in Greenbelt, Md., NASA's Jet Propulsion Lab in Pasadena, Calif., and University of California at Berkeley.

The engineers will watch the ARTEMIS P1 orbit closely over the next few days in case additional adjustments are required. Engineers are set to move the second spacecraft, ARTEMIS P2, into position on July 17.

ARTEMIS is the first mission ever to orbit the moon's Lagrangian points – points on either side of the moon where the moon and Earth's gravity balance perfectly. It is also the first to attempt to move from the Lagrangian to lunar orbit.

The ARTEMIS mission uses two of the five in-orbit spacecraft from another NASA Heliophysics constellation of satellites called THEMIS that were launched in 2007 and successfully completed their mission in 2010. The ARTEMIS mission allowed NASA to repurpose two in-orbit spacecraft to extend their useful science mission.

Follow the full story, HERE.

Update on new lunar phase of THEMIS mission

Michael Barkoviak
UC Berkeley Daily Tech

"The NASA THEMIS satellite mission, which launched in 2007 ... using five identical satellites" in Earth orbit "researchers are able to successfully measure the local magnetic field and properties of the particles trapped in the magnetic field."

"Two of the five THEMIS probes are now on their way to the moon, for a new life studying the lunar environment"... "Although the two-year 'prime mission phase' of THEMIS is now over, three of the THEMIS probes, closest to the Earth, will continue to operate (for many years) collecting scientific data about the solar wind interaction, space weather, geomagnetic storms, etc."

"Although there are concerns of fuel levels, researchers will have the probes utilize complex orbits that will involve flying them by the moon using Lagrange points to help reduce fuel consumption."

Instead of launching a new mission, researchers decided to send the probes to the moon. Dubbed 'ARTEMIS,' the two space probes ... will conduct several flybys of the lunar surface later this year, then will go into orbit.

Read the original article, HERE.

ARTEMIS to Lagrange points to lunar orbit

THEMIS P1 (TH-B) in red and P2 (TH-C) orbit between this summer's orbit raise maneuvers and October 2010 when they will capture the Lagrange points between Earth and Moon. After six months in these orbits, P1 and P2 will be inserted into Lunar orbits where they will make measurements of the Lunar warke, the magnetotail, and solar wind through September 2012. See Larger Image HERE.

THEMIS will continue with five probes, saving two by sending them on a long and important detour through Earth-Moon Lagrange points to equatorial lunar orbit.

Sometime in May final approval should be given to save two of the five co-orbiting satellites in the successful THEMIS constellation by diverting these to Earth-Moon Lagrange points and eventually into lunar orbit for a 17 month stay.

Needed study of the lunar exosphere and of the Moon's wake within the solar wind and within the magnetotail of Earth will be added to THEMIS exceptional primary mission in a challenging and complex set of orbital manuvers.

ARTEMIS will become a distinct component of THEMIS and its ongoing continuing study of the solar wind and its complex interactions with Earth's magnetosphere, as an expected sharp increase in solar activity as Solar Cycle 24 gets underway, while also gathering a unique and needed dataset in vicinity of the Moon prior to extended human activity.

THEMIS (Time History of Events and Macroscale Interactions during Substorms) should be expanded to include ARTEMIS (Acceleration, Reconnection Turbulence and Electrodynamics of Moon's Interaction with the Sun).

In planning for THEMIS at the University of California at Berkeley, principal investigator V. Angelopoulos and his team knew they would have a problem soon after their primary mission was accomplished. If the P1 and P2 satellites in the five probe constellation were not adjusted in their orbits. It was announced March 20 that the THEMIS primary mission had been completed. Each of the five probes remain in excellent health.

Nevertheless, because of their initial orbital configurations, P1 and P2 are eventually headed into extended periods in Earth's shadow, and outside their solar battery's recharging design range. That initial orbital configuration was obviously necessary because the five probes set in motion a vast opportunity to gather data and make new discoveries, documented in at least 30 papers.

The new "ARTEMIS component" of THEMIS will begin an ascent toward the Moon beginning late 2009, and the basic five vehicle mission will be able to continue. As the ARTEMIS component is manuvered through the Earth-Moon Lagrange points, and eventually into lunar orbit, study can begin strongly complementing the Lunar Reconnaissance Orbiter and LADEE missions.

The complex orbital manuver will take nearly two years, but will enabling THEMIS to continue it's baseline mission without the loss of two of the five probes. (See diagram, page 29 of the Proposal submitted by the THEMIS team last summer, HERE.)

Road Cleared for ARTEMIS (THEMIS News & Events, February 27, 2009)

On Feb 24, 2009 ARTEMIS passed its mini-Confirmation review at (Goddard Space Flight Center). Therefore, the road has been cleared for the upcoming mission implementation. There will be a delta (pico) review in early May to ensure progress with contingency planning is adequate, but we don't anticipate any problems. Congratulations to the implementation teams at UCB, JPL and GSFC for their outstanding progress to-date!

The essence of the comments of the review board was that the ARTEMIS team has done an outstanding job, especially considering the little (8 months) time that has passed since the Senior Review go-ahead. Of course, it was recognized that there is still a lot of work ahead, but the team yesterday presented a reasonable, viable plan, which conveys confidence they can deliver. Even though this is a challenging project, given the resources and time available, this condition was deemed acceptable considering that the THEMIS probes are already operating well and this is an extended-phase mission. The reviewers have come up with less than a handful of requests for action, which I am certain will strengthen the project, as it moves towards the Orbit Raise Maneuvers in the upcoming summer. Tentatively the ORMs start July 9th.

Please find the extended THEMIS proposal HERE.
Please find the Senior Review report HERE.