Radio amateurs set course for the Red Planet

‘Open source’ Google Lunar X Prize contestant Team FREDNET, who we have written about before, operates under a contest requirement stating that no more than %10 of the funds spent by their mission to the Moon may stem from government sources. If Team FREDNET is successful, their mission will truly demonstrate that private initiative alone is enough to reach the surface of a celestial body, and, by their mission’s open nature, pave the way for anyone else, who neither have access to a goldmine of taxes, to do the same.

But if you do allow yourself to be guided, to some degree, by public policy, and thus make your mission eligible to public funding, you can reach even further – even if you insist to work under the full, unrestrictive disclosure that characterize open space exploration.

AMSAT-DL, the German chapter of the international amateur satellite organization AMSAT, is set to prove this in late 2010 to early 2011, when their P5-A probe is to launch from the Earth to begin a year-long voyage towards our closest planetary neighbor, Mars.

Until now, Mars has exclusively been the destination of national space agencies, and the Martian surface, due to the repeated failure of landing probes sent by Russian and European agencies, the sole territory of NASA.

And while AMSAT-DL’s 30 years of experience with space so far is limited to satellites orbiting the Earth, NASA’s two most stalwart scouts on the Red Planet, the rovers Spirit and Opportunity, as well as NASA’s planned Mars Science Laboratory, should not get too comfortable with the title of being the only Earthen probes operating at the surface of Mars.

AMSAT-DL is considering sending a secondary payload, possibly a lander, along with their primary P5-A satellite to Mars, which could for instance collect images and other data from the Martian surface and relay it through the orbiting P5-A back to Earth.

Deployment and inflation test of a full-scale model of ARCHIMEDES baloon inside the Olympia Hall, Munich.

Deployment and inflation test of a full-scale model of ARCHIMEDES baloon inside the Olympia Hall, Munich. (Source: Mars Society Germany)

In particular, the German branch of the Mars Society has an open proposal for a payload, known as ARCHIMEDES, that would separate from P5-A and initiate a descent towards the Martian surface using a small solid-fuel rocket. A heat shield would decelerate the payload, and at an altitude of about 10 kilometers above the surface, a balloon would unfold and inflate. The balloon would then carry the remaining payload and its scientific instruments around Mars a few times, taken along by the high velocity winds of the upper Martian atmosphere, and send pictures and other data of this flight back to P5-A. The ARCHIMEDES vehicle has already been developed and tested extensively by the Mars Society.

Another, technically simpler, proposal for a secondary or ‘sub-satellite’ payload calls for small satellites with a side length of about 10 cm (pico-sats) to separate from P5-A in Martian orbit, enter their own orbit, and establish radio contact with each other. Using a technique called radio occulation, whereby the propagation time of radio signals sent by the small satellites are measured to construct an exact profile of the atmosphere at a given point, the pico-sats may be able to identify regions on Mars that still hold liquid water. This information would be highly valuable to later manned missions to the Red Planet.

With such sophisticated payloads on AMSAT-DL’s hands, it can seem a somewhat daunting leap to go straight from AMSAT’s core competence of Earth-orbiting satellites, which are thoroughly understood and supported by communications infrastructure on the Earth, to something as exotic as an interplanetary probe – why not try with a celestial body a bit closer to home, such as the Moon, first?

AMSAT-DL argues that any orbit around the Moon is inherently unstable due to the relatively close proximity, and thus gravitational pull, of the Earth. Preventing a hypothetical radio amateur satellite orbiting the Moon from being “sucked” back to Earth by gravity is simply too difficult.

Furthermore, the total change of velocity (the so-called delta-v), and thus resources, required to reach Mars is only minimally different from the velocity required to reach the Moon. For a robotic probe, a Martian voyage is, in other words, not significantly more expensive than one to the Moon.

Rather, the main differences are the duration of the voyage – a typical transfer to the Moon takes about a week, while a transfer to Mars may take up to around a year – and the power required to establish radio links with the probe at its final destination, being much farther away (the Moon is around 0.002 AU away from the Earth, Mars between 0.5 and 2.5 AU away).

P5-A will rely on the structure and propulsion systems developed for P3-D, another satellite designed by AMSAT-DL, and now gone into Earth orbit under the name OSCAR-40 (in short, AO-40). The experience gained by AMSAT from operating AO-40 for the past 8 years will serve as a good basis for sending a similar system towards Mars.

An incident on the AO-40, shortly after launch in 2000, disabled a number of subsystems on the satellite, and for a while threatened to terminate the mission. After several weeks of silence, radio links to the satellite were finally reacquired, and most important subsystems restored. It later turned out that a plugged valve in the satellite’s fuel system had, by a sequence of events, caused a small explosion in the satellite. Experiences like this, and the subsequent recovery from them, will give the AMSAT engineers a better understanding of which challenges they are up against when P5-A is going for Mars. Furthermore, the AO-40 mission will prepare radio amateurs around the world to pick up signals with characteristics similar to those to be sent by P5-A.

AMSAT-DL intend to use a radio observatory in Bochum, Germany as their primary ground station. The station, which is equipped with a 20 meter parabolic antenna, has been in operation since receiving the first signals from Sputnik 1, the world’s first man-made satellite, 50 years ago, and proved it’s Martian capabilities in 2003 when, on behalf of AMSAT-DL, it successfully received signals from ESA‘s Mars Express probe on its way to the Red Planet. Later, in 2006, AMSAT-DL’s team at the station received a signal from NASA’s venerable Voyager 1 probe, the most distant man-made object in the universe ever, at a distance of as much as 98 AU, or 40 times the distance from the Earth to Mars.

Sternwarte Bochum radio observatory in Bochum, Germany.

Sternwarte Bochum radio observatory in Bochum, Germany.

But don’t let the expensive-looking radome in Bochum scare you off. AMSAT-DL ensures us that, in true radio amateur style, signals from P5-A orbiting Mars will be receivable with an off-the-shelf 1.2 meter dish throughout the mission, and when Mars’ orbit around the Sun comes the closest to Earth’s, with as little as a 30 centimeter dish. AMSAT-DL estimates that for 9 months out of a 26 month period, signals from P5-A will be receivable with simple equipment available to the average radio amateur. The big dish in Bochum will be used for high bandwidth, low noise communications as well as emergency communications when weaker receivers are not sufficient.

Transmitting signals to P5-A requires a somewhat less standard setup, but should be possible, provided that the communications does not interfere with AMSAT-DL’s mission.

AMSAT-DL urges radio amateurs all over the world to prepare to tune into P5-A when it has entered orbit and goes out-of-sight for the primary command stations (e.g. the one in Bochum), and upload received telemetry data to AMSAT-DL’s central servers.

While a true radio amateur satellite, designed under ‘open source’ terms and conditions, P5-A relies indirectly on a great degree of government funding – for instance in the form of labor and hardware contributed by involved universities. It has also been suggested that P5-A can act as a much wanted alternative relay for the many planned government surface missions to Mars in the coming years, such as the already mentioned Mars Science Laboratory rover from NASA, and ESA‘s ExoMars rover, which would be another indicator of the mission’s ties to tax money.

Should the design of the probe turn out to be successful, however, it’s freely available specifications will enable anyone with the necessary funds – including private investors – to attempt the launch of another craft based on P5-A’s design. And AMSAT-DL’s demostration that ‘it can be done’ will obviously make investors much more likely to throw money at such a challenging venture. One might, in other words, hope that AMSAT’s mission could kickstart private development of interplanetary spacecraft – which in turn could have far-reaching implications for human exploration of space in general.

AMSAT-DL’s P5-A is set to enter orbit around Mars in August 2012.

Advertisements

About this entry