Will NASA Recover Apollo 13's Plutonium 238?

Apollo 13 Astronaut Fred Haise extracts the fuel element for the SNAP-26 RTG during training

Credits: NASA

Somewhere among the jagged trenches of the South Pacific sits a graphite fuel cask containing 3.9 kg of plutonium from Apollo 13.

The fate of the radioactive plutonium-238 has long been overshadowed by the successful return of the three NASA astronauts on board the ill-fated mission.

The plutonium was supposed to fuel the System for Nuclear Auxiliary Power, or SNAP-27 Radioisotope Thermoelectric Generator (RTG), designed to power a set of experiments on the lunar surface but after an explosion crippled the craft and forced the crew to abandon plans of a lunar landing, the plutonium became yet another problem for mission control.

Officials from NASA confidently told The New York Times that the biggest risk was that the 40-pound generator might hit someone when it fell to Earth.

“It will keep a few fish warm,” a NASA official said. The Atomic Energy Commission, on the other hand, conceded the slight possibility that it could become ground into dust and dispersed.

NASA learned its lessons about engineering the fuel casks the hard way: in 1964, the Transit-5-BN mission aborted and the RTG burned up upon reentry above Madagascar, in keeping with its design.

Traces of plutonium were found in the area months later. In 1968, the Nimbus B-1 weather satellite was aborted soon after takeoff from Vandenberg Air Force Base and the plutonium from the SNAP-19B2 RTG plunged into 300 feet of water off the California coast, with no release of radiation.

Apollo 13’s SNAP-27 fuel, as far as we know, slipped beneath the waves and came to rest 6 to 9 kilometers deep in the Tonga Trench, one of the deepest areas in the ocean.

Subsequent testing by the U.S. Department of Energy has shown no spike in background radiation.

Not surprisingly, NASA has no desire to go looking for the small cask, even with advances in submersible technology that would make such a mission at least technically feasible.

“I don’t think that anyone has seriously considered that because of the cost of recovery,” said Leonard Dudzinski, a NASA program executive who deals with radioisotope power systems.

President Nixon (right) presenting the nation’s highest civilian award to the Apollo 13 crew (left to right, J. L. Swigert, F. W. Haise, J. A. Lovell) 

Credits: NASA

Indeed, NASA is trying to source additional plutonium 238 for its future deep space missions, the U.S. no longer produces the isotope and Russia has proved to be an unreliable source, but the useful life of the Apollo 13’s plutonium has expired.

The plutonium poses little danger to the environment: the corrosion resistant cladding should withstand seawater for approximately 870 years, ten times the plutonium’s half life.

According to NASA, the plutonium itself was in oxide form and was both chemically and biologically inert when it plunged into the ocean.

Over the years, the plutonium cask, far out of sight, has fueled two contradictory positions on the safety of RTGs for deep space missions.

For NASA, its safe return to Earth proved the effectiveness of their safety engineering. “We recognize that the Apollo 13 [RTG system] worked,” Dudzinski said. “Follow on RTGs were based on that design and improved on that design.”

Critics have taken different lessons from the untimely plunges of the RTGs. In 1997, a group of safety experts, including physicist Dr. Michio Kaku, warned that 32 kg of plutonium contained in the Saturn-bound Cassini satellite posed a greater danger than NASA would acknowledge, but ultimately, their warnings did not prevented the mission from happening.

NASA Mars Curiosity Rover: MAHLI Captures a mosaic of Mars

A mosaic of MSL MAHLI images acquired on Sol 613. CLICK on the photo to see the full image

Credit: NASA /JPL-Caltech /MSSS

This is Curiosity's latest "selfie," a mosaic made up of about a dozen images acquired with the rover's Mars Hand Lens Imager (MAHLI) instrument on April 27-28, 2014 (Sol 613).

The 5.5-km-high Mount Sharp (Aeolis Mons) rising in the background.

There are plenty of discrepancies in the mosaic tiling but, some say, it imparts some character to Curiosity.

Visible in the mosaic are Curiosity's cylindrical RUHF antenna and a bit of her Radioisotope Thermoelectric Generator (RTG) visible in the lower center.

NASA Mars Rover 2020: Next Mars Rover to Seek Signs of Life

A sketch of the design for NASA's 2020 Mars rover. 

Planning for NASA's 2020 Mars rover envisions a basic structure that capitalises on re-using the design and engineering work done for the NASA rover Curiosity.

NASA rover Curiosity landed on Mars in 2012, but with MSL, the new science instruments selected through competition for accomplishing different science objectives with the 2020 mission.

CREDIT: NASA/JPL-Caltech

NASA's next Mars rover should hunt for signs of past Red Planet life and collect samples for eventual return to Earth, a team of mission planners has determined.

The new Mars rover — slated to launch in 2020 — should explore a site that once was habitable, make its own observations and snag material for scientists here on Earth to study in unprecedented detail at some point in the future, according to a new report compiled by the mission's "science definition team" (SDT).

"The SDT-preferred mission concept employs new in situ scientific instrumentation in order to seek signs of past life (had it been there), select and store a compelling suite of samples in a returnable cache and demonstrate technology for future robotic and human exploration of Mars," states the report, which was released to the public today (July 9).

The 2020 Mars rover will be based heavily on NASA's Curiosity rover, which touched down last August on a mission to determine if Mars could ever have supported microbial life.

For example, the new robot will use a similar chassis and "sky crane" landing system, NASA officials have said. But the 2020 rover will take the science to a whole new level.

"The 2020 rover as proposed by the Science Definition Team would carry a different and more advanced set of science instruments than Curiosity carries, its drill would extract cores rather than blended powder from rocks and it would collect and package samples for possible future return to Earth," NASA officials wrote today in an FAQ about the SDT's report.

Just what those instruments will be is unclear at the moment; they will be selected through a competitive process but the science gear will search for visual, mineralogical and chemical signs of past life if the SDT recommendations are adopted.

"The capability for examining the mineralogic composition of samples at microscopic scale would be unprecedented for a mission to Mars," NASA officials wrote in the FAQ.

"The search for potential signs of past life could use assessments of textures, shapes, mineralogy, organic-matter content, and possibly elemental chemistry at the scale of individual grains within a sample."

The rover would also gather and store samples for potential return to Earth by a future mission (the timing and details of which are yet to be determined).

Sample-return is viewed by most scientists as the best way to look for signs of Red Planet life.

The new rover's landing site has not been selected yet, officials said, and its power source similarly has not been confirmed.

The Mars Science Laboratory rover, Curiosity, took this self portrait, which shows its Radioisotope Thermoelectric Generator (RTG) at center

Curiosity is powered by a radioisotope thermoelectric generator (RTG), which converts the heat generated by radioactive decay into electricity.

The 2020 rover may follow suit, but it's also possible that it could run on solar power, like NASA's smaller Spirit and Opportunity rovers, which landed on Mars in 2004.

"No final decision on a power source for the 2020 rover would be made until the mission completes a review through the National Environmental Policy Act process, which considers the environmental impacts of launching and conducting the mission," NASA officials wrote in the FAQ.

Curiosity's mission cost a total of $2.5 billion. The 2020 rover is expected to be significantly cheaper, with a total price tag estimated at around $1.5 billion.