Humanity has been a spacefaring species for barely sixty years now. In that brief time, we’ve fairly mastered the business of putting objects into orbit around the Earth, and done so with such gusto that a cloud of both useful and useless objects now surrounds us. Communicating with satellites in Earth orbit is almost trivial; your phone is probably listening to at least half a dozen geosynchronous GPS birds right now, and any ham radio operator can chat with the astronauts aboard the ISS with nothing more that a $30 handy-talkie and a homemade antenna.
But once our spacecraft get much beyond geosynchronous orbit, communications get a little dicier. The inverse square law and the limited power budget available to most interplanetary craft exact a toll on how much RF energy can be sent back home. And yet the science of these missions demands a reliable connection with enough bandwidth to both control the spacecraft and to retrieve its precious cargo of data. That requires a powerful radio network with some mighty big ears, but as we’ll see, NASA isn’t the only one listening to what’s happening out in deep space. Continue reading “Serious DX: The Deep Space Network”
ISEE-3, the plucky interplanetary spacecraft fueled by the dreams of thousands of crowdfunding backers and hydrazine is now transmitting data to Earth.
Where all radio contact with ISEE-3 this year has only been a carrier frequency, the folks at the reboot project have successfully commanded ISSE via the huge Arecibo telescope to transmit data back to Earth. Usable data are now being received at 512 bits/second at ground stations in Germany, Kentucky, and California, surely being looked over by the ISEE reboot project engineers.
Simply transmitting the commands to put the data multiplexers into their engineering telemetry mode was no small task; a power amplifier needed to be built, shipped to Arecibo, and installed in the giant dome hanging over the Arecibo dish. The amplifier was only installed in the last day, during an earthquake, no less.
There’s still a lot of work to be done before the project can go any further; the team will need to check the status of the spacecraft from the data received, more systems will be checked out, and eventually the spacecraft will be commanded to perform a 17-hour long burn with its small thrusters, putting it on course to be captured by Earth some time in August.
It’s an amazing achievement to do any sort of communication on this scale, and now events in the ISEE-3 mission timeline will be coming rather quickly. We’re trying to organize a video/blog/cast thing with the team from NASA Ames or Morehead State, but the team is, understandably, a little busy right now.
Out in the depths of space, more than 100 times the distance from the Earth to the moon, there’s a lonely spacecraft gracefully spinning towards an August encounter with our planet. It’s ICE/ISEE-3, a probe long-forgotten by official space agencies. Now, the team dedicated to repurposing this satellite has made contact with this probe using a 20-meter satellite dish in Germany.
When we first heard about the planned communication by volunteers, no one was certain the probe was still alive. It shouldn’t be a surprise this satellite was still functioning; it was launched in 1978, and most of the instruments were still functioning in 2008. Still, this is the first time amateurs – not NASA – had received a signal from the probe
ICEteam, the group of volunteers dedicated to reviving this spacecraft used the huge dish at Boshum observatory to detect the 5 Watt carrier signal coming from the spacecraft. That’s all the probe is sending out right now – no data was received – but this is a huge accomplishment and the first step towards directing ICE/ISEE-3 into an orbit around one of the Earth-Sun Lagrange points.
Side note: Looking at the ephemeris data (target -111) I *think* ICE/ISEE-3 will be above the night side of Earth at closest approach. Can anyone confirm that, and does that mean a future mission at L2?
Video from the ICEteam below.
Continue reading “ISEE-3: We Get Signal”
ISEE-3, one of America’s most dedicated space exploration vessels is on its way home. Unfortunately, when it gets here, no one will be talking to it. NASA decommissioned the equipment needed to communicate with the satellite nearly 15 years ago. [Emily Lakdawalla] at the planetary society has been following the long traveled probe for years. Her recent article on the topic includes the news that NASA essentially gave up the battle before it even started.
Originally named International Sun/Earth Explorer 3 (ISEE-3), the spacecraft was launched atop a Delta rocket on August 12, 1978. Its mission was to study interaction between the Earth’s magnetic field and solar wind. As part of this mission ISEE-3 became the first spacecraft to enter halo orbit. It did this by positioning itself at Lagrangian point L1, directly between the sun and the Earth. In 1982, scientists on earth were preparing for the 1986 flyby of Halley’s Comet. ISEE-3 was repurposed as a comet hunter, and renamed International Cometary Explorer (ICE). The craft flew back to Earth and entered lunar orbit, coming within 120km of the moon’s surface. It used this momentum to achieve a heliocentric orbit, on track for two comet encounters. ICE/ISEE-3 encountered Comet Giacobini-Zinner on September 11, 1985, collecting data and becoming the first spacecraft to fly through a comet’s plasma tail. While not considered part of the Halley Armada, ICE/ISEE-3 took measurements as it passed within 28 million km of Comet Halley’s nucleus. Since then, ICE/ISEE-3 has continued on its 355 day heliocentric orbit. It studied coronal mass ejections in the early 90’s, before being shut down in May of 1997. Follow us past the break to learn ICE/ISEE-3’s fate.
Continue reading “Call for Hams and Hackers: Welcome ICE/ISEE-3 Home”