Day: December 31, 2017

Back in August I wrote about a proposal from the Johns Hopkins Applied Physics Laboratory (APL) to fly a robotic helicopter to Saturn’s moon Titan.

Called “Dragonfly”, the mission would use a nuclear-powered dual-quadcopter, an evolution of drone technology, carrying a suite of science instruments to study the moon. Capable of vertical take-off and landing (VTOL) operations, the vehicle would be able to carry out a wide range of research encompassing Titan’s atmosphere, surface, sub-surface and methane lakes to see what kind of chemistry is taking place within them.

The proposal was one of several put forward for consideration by NASA as a part of the agency’s New Horizons programme for planetary exploration in the 2020s. In late December 2017, NASA announced it was one of two finalist proposals which will now receive funding through until the 2018 for proof-of-concept work.

Titan has diverse, carbon-rich chemistry on a surface dominated by water ice, as well as an interior ocean. It is one of a number of “ocean worlds” in our solar system that hold the ingredients for life, and the rich organic material that covers the moon is undergoing chemical processes that might be similar to those on early Earth. Dragonfly would take advantage of Titan’s dense, flight-enabling atmosphere to visit multiple sites by landing on safe terrain, and then carefully navigate to more challenging landscapes.

At 450 kg, Dragonfly is no lightweight, and a fair amount of the mass would be taken up by its nuclear power unit. However, the vehicle will carry a science package comprising some, or all, of the following:

• A mass spectrometer for analysing the composition of Titan’s atmosphere and surface material.
• A gamma ray spectrometer of analysing the shallow sub-surface.
• A seismometer for measuring deep subsurface activity.
• A meteorology station for measuring atmospheric conditions such as wind, pressure and temperature.
• An imaging system for characterising the geologic and physical nature of Titan’s surface and identifying landing sites.

Commenting on the NASA decision to provide further funding for the project, APL Director Ralph Semmel said:

This brings us one step closer to launching a bold and very exciting space exploration mission to Titan. We are grateful for the opportunity to further develop our New Frontiers proposals and excited about the impact these NASA missions will have for the world.

The second proposal to receive funding through until the end of 2018 is the Comet Astrobiology Exploration Sample Return (CAESAR) mission proposed by Cornell University, Ithaca, New York and NASA’s Goddard Space Flight Centre.

This mission seeks to return a sample from 67P/Churyumov-Gerasimenko, a comet that was successfully explored by the European Space Agency’s Rosetta spacecraft, to determine its origin and history. This project is being led by Steve Squyres of Cornell University, who was the principal investigator for NASA’s Mars Exploration Rover missions featuring Opportunity and Spirit.

If approved by NASA, CAESAR would launch in 2024/25, collect at least 100 g (3.5 oz) of regolith from the comet, separating the volatiles from the solid substances. The spacecraft would then head back to Earth and drop off the sample in a capsule, which would re-enter Earth’s atmosphere and parachute down to the surface in 2038. 67P/C-G was selected because it has been extensively imaged and mapped by the Rosetta mission, thus enabling engineers to design a vehicle better able to meet the conditions around the comet as it swings around the Sun.

New Frontiers is a series of planetary science missions with a cap of approximately US $850 million apiece. They include the Juno mission to Jupiter, the Osiris-REx asteroid sample-return missions, and the New Horizons mission to Pluto, also built and operated by APL. Under the terms of NASA funding, both of the 2017 finalists will receive US $4 million each in 2018, and a final decision on which will be funded through to completion will be made in 2019.

WFIRST: Hubble’s New Cousin

While attention is on the next space telescope due for launch – the ambitious James Webb Space Telescope (JWST), which will be departing Earth in 2019 – NASA and the international community is already turning its attention to the telescope that will come after JWST, with a launch due in the mid-2020s.

Billed as a cousin to the Hubble Space Telescope, and something of a descendent of that observatory, the Wide Field Infra-Red Survey Telescope (WFIRST) will use a very similar telescope system as Hubble, with a 2.4m diameter primary mirror, but with a shorter focal length. This, coupled with no fewer than 18 sensors built into the telescope’s camera (Hubble only has a single sensor), means that WFIRST will be able to image the sky with the same sensitivity as Hubble with its 300-mexapixel camera – but over an area 100 times larger than Hubble can image. To put this in perspective: where Hubble can produce a poster for your living room wall, an image from WFIRST can decorate the entire side of your house.

This wide field of view will allow WFIRST to generate never-before-seen big pictures of the universe, allowing astronomers explore some of the greatest mysteries of the cosmos, including why the expansion of the universe seems to be accelerating. One possible explanation for this speed-up is dark energy, an unexplained pressure that currently makes up 68% of the total content of the cosmos and may have been changing over the history of the universe. Another possibility is that this apparent cosmic acceleration points to the breakdown of Einstein’s general theory of relativity across large swaths of the universe. WFIRST will have the power to test both of these ideas.

Continue reading “Space Sunday: helicopters, telescopes and cars in space” →