Economic instability and budgetary concerns have significantly eroded NASA’s exploration mission, forcing a shift away from manned missions and toward less costly, less risky robotic missions.
Following the termination of the space shuttle program last month, NASA will now likely expand its focus on near-Earth asteroid exploration and robotic missions to other planets and moons in our solar system.
When that happens, the Laurel-based Johns Hopkins University Applied Physics Laboratory (APL) will find itself uniquely poised to contribute. Its successes stretch back to the launch of the TRANSIT 2 satellite in 1960 and have yielded a wealth of interplanetary know-how.
APL also took the lead in 1994 by working with the International Academy of Astronautics (IAA) to establish a recurring International Conference on Low-Cost Planetary Missions. APL hosted the most recent conference in June this year, and was also host for the first and fourth conferences in 1994 and 2000, respectively.
A number of factors in the early 1990s influenced the need for such a conference, said John Sommerer, head of the APL Space Department.
“Costs were so high for flagship missions, like Apollo, that NASA established a new category of competitive missions to stimulate creativity and innovation,” Sommerer said. “These Discovery Program missions include a good mix of scientists and engineers, so we wanted to do something that could address both groups at the same time,” while also potentially lowering costs by encouraging international cooperation.
The Japan Aerospace Exploration Agency (JAXA) and the Israel Space Agency were among the largest contingents attending this year’s international conference.
When it comes to international cooperation, Sommerer said he is most intrigued with the Japanese agency, particularly from an instrumentation and ion drive propulsion standpoint.
“In some respects, the JAXA program is very compatible with our small set focus,” he said. “Almost all of their programs are low-cost, their labor rates are similar and they try to squeeze as much as possible out of each mission. It’s not so much the destinations, but the evolution of these [missions] that’s so important.”
Discovery missions were understood to be fly-by or orbiter operations, “but people are starting to consider how far we can push the low-cost paradigm,” Sommerer said. “We ought to be looking hard at all chances to push the cost down — can you get a sample return out of it?”
Experience has shown that partnering with other countries can help drive that cost down.
“India’s Chandraayan-1 mission cost was dizzyingly small compared to what it would cost us to do it today,” he said, referring to the mission that took APL’s Mini-RF instrument to the moon in 2008 aboard NASA’s Lunar Reconnaissance Orbiter.
The downside, however, is added risk, considering the potential for integration and timeline problems when working across cultural and other operational channels.
APL’s past successes provide some insight into what is possible with low-cost missions. And as robotic missions go, Voyager 1 set the achievement bar high. (Combined total cost for Voyager 1 and Voyager 2 up to the Neptune encounter in 1982 was $865 million.)
Launched in 1977, the Voyager 1 is now approaching the point where the solar wind — a stream of charged particles emitted by the sun — gives way to the interstellar space of the Milky Way Galaxy.
“On the basis of the data we’ve had, Voyager 1 should enter the interstellar medium in 2012,” said Stamatios Krimigis, principal investigator for the instrument.
Equally exciting for APL is that fact that, after 34 years and nearly 11 billion miles, its Low-Energy Charged Particle instrument aboard Voyager 1 is still transmitting information.
“It’s in remarkable shape for 1970s technology,” Krimigis said, still responding to the tweaks and new commands that now take roughly 16 hours and 15 minutes to reach it from Earth via radio waves traveling at the speed of light.
Voyager 1’s current mission is to determine how far the sun’s particles penetrate into the galactic medium. Once beyond their detection range it will begin a new mission, Krimigis said, studying the galactic magnetic field and trying to determine the source of cosmic rays.
“It will be making brand new discoveries in uncharted territory,” he said, “but we’re in a race between the power supply and Voyager’s ability to provide electricity to its instruments.”
In response, APL has developed an electricity time share plan for the onboard instruments, trying to keep all five functioning on a rotating basis until 2025, when APL expects to lose contact with Voyager 1.
Closer to home and part of the Discovery Program, APL’s MESSENGER spacecraft entered orbit around Mercury in March this year. This mission will provide the first complete reconnaissance of the planet’s geochemistry, geophysics, geologic history, atmosphere, magnetosphere and plasma environment.
MESSENGER could help scientists understand why Mercury is so dense and why it has a magnetic field.
“One hypothesis is that it has an inner iron core,” said Project Scientist Ralph McNutt.
Years ago, radar reflections around the poles also suggested the existence of water ice on one of the hottest places in the solar system.
“We were able to verify that some craters have been in permanent shadow for at least the last billion years and are cold traps where ice could exist,” McNutt said.
Mercury may also hold clues to the solar system’s formation.
“It’s one of four so-called terrestrial planets that formed in the same relative part of the solar system, but they’re vastly different,” he said. “Life actually developed on one, and we’d like to understand what went so differently in this part of the solar system to allow that.”
MESSENGER’s findings will help scientists piece together a consistent story of Mercury’s observable magnetic field and what they can deduce from its gravity field to determine how much of a core it has. “We’re interested in the chemical makeup of its surface, how the planet was put together and what it looks like underneath the surface,” McNutt said. “These are not simplistic notions, because the theories we’ve had so far don’t work.”
At less than $450 million, MESSENGER’s beefed up, lingering mission comes in at roughly the same cost in today’s dollars as the fly-by mission of Mariner 10, which was launched in 1973.
Last month saw the launch of APL’s Jupiter Energetic-particle Detector Instrument (JEDI) aboard NASA’s Juno spacecraft. JEDI will measure energetic particles that flow through and are trapped within Jupiter’s magnetosphere. That interaction generates bright northern and southern lights, called aurora, that are the most powerful in the solar system.
Juno will reach Jupiter in 2016 and circle its poles for a year.
“We really want to know what happens in the aurora that causes these particles to accelerate to such high energies,” said Barry Mauk, JEDI lead investigator.
“We must study the planet to make the connection between such
Earth-space phenomena as auroras, radiation belts and magnetic field dynamics,” said Mauk. “We’d like to have a more predictive understanding of Earth’s own space environment, which is important
for practical decisions regarding the future of spaceflight and manned missions.”