Wednesday, 9 July 2014

Switching Off Space Missions

Canada's MOST satellite, launched in 2003. CSA image

When Canada's first satellite, Alouette 1, was launched in 1962, engineers estimated that it would last for a year. Alouette was so advanced that some Americans expected that the satellite would operate for a far shorter time, but in fact it was still going strong ten years later when Canadian officials ended the mission and turned Alouette off. The same fate awaited Alouette 2 after a decade of service, and when Canada's third satellite, ISIS-1, had completed 15 years on orbit, control was turned over to Japanese scientists who continued its research for another five years.

From the beginning, Canada has had the enviable problem of what to do with robotic spacecraft that keep operating long beyond their projected lifetimes, an issue which has popped up again with Canada's first  astronomy satellite, known as MOST, which has been in orbit since 2003. MOST (the acronym stands for Microvariability and Oscillations of STars) is a low-budget satellite about the size of large suitcase that tracks individual stars for long periods of time to detect minute variations in light levels that reveal what is going on inside the star.

Although MOST, which has been nicknamed the Humble Space Telescope, doesn't take pretty pictures like the more famous Hubble Telescope, it has produced solid, important and often surprising science for astronomers. The astronomers who operate MOST, led by Jaymie Matthews of the University of British Columbia, understandably want MOST's mission to continue.

Even a low-cost $10 million satellite needs $300,000 a year to operate, and now Matthews is looking for corporate support to keep MOST in operation. Funds from Europe are also being sought to present MOST from being switched off on September 9, and I wouldn't be surprised if the MOST scientists also look into crowd funding.

This issue isn't restricted to Canada. In the United States, with its wide open budget battles between NASA, the president of the day, the U.S. Senate and the House of Representatives, threats are often made to prematurely end robot missions. Hubble itself was in danger a decade ago, but in that case, the issue revolved around whether it was safe to send one more space shuttle servicing mission to Hubble before the shuttle program ended in 2011. In the end, NASA relented in the face of public demand, and launched a shuttle servicing mission that extended Hubble's life to the present day.

This year NASA has made known a plan to end the mission of the Spitzer Space Telescope in 2015. Spitzer, one of the "Great Observatory" missions that include Hubble, images celestial objects in the infrared and has been flying a limited mission since coolant in its camera ran out in 2009. Now it is under threat of being shut off due to "constrained budget conditions."

Even well-known missions, including Mars rovers and the Cassini spacecraft orbiting Saturn, have been threatened with curtailment for budget reasons, although their high profile status has usually saved them. 

Other ongoing missions have not fared so well. For example, the Apollo Lunar Surface Experiments Packages that were deployed on the Moon by astronauts from Apollos 12, 14, 15, 16 and 17, were switched off on September 30, 1977, for budgetary reasons (Apollo 11's seismometer had lasted only a short time). 

In the case of MOST, one feels for the great work being done by its scientists, and wonders what might be discovered if MOST were given a longer lease on life. But other Canadian astronomers with other research interests are waiting with varying degrees of patience for funding for their own space-based instruments, which might get the go-ahead for launch and discoveries of their own when the MOST funds are freed up. 

An even better solution would be for our federal government to spend more on space, but with austerity being the order of the day and the decision being left to a government not known for its enthusiasm for science, that is a distant dream.

On a happier note, we are currently watching the resurrection of a spacecraft whose switch was turned off seventeen years ago. ISEE-3 (for International Sun-Earth Explorer) was launched in 1978 into a highly unusual 'halo' orbit around an Earth-Sun Lagrangian point. After its original mission ended, ISEE-3 was repurposed as the International Comet Explorer and became the first spacecraft to encounter a comet, in this case Comet Giacobini-Zinner in 1985.

This year a private group of space enthusiasts, including engineers and scientists, many of them former NASA employees, launched a crowd funding effort. More than $150,000 has been raised, and after NASA agreed to the plan and the reboot team dug through archives to determine how to contact and operate the spacecraft, they fired ISEE-3's thrusters last week for the first time since 1997.

Still more work needs to be done to make this project a success, but it offers a glimmer of hope to those whose spacecraft has been turned off or faces termination by budget.

No comments:

Post a comment