Pluto, measuring gravity with probe swarms and more!

A lot of exciting space science news coming in this weekend! Lets start with this project brief from Johns Hopkins University.

The proposal is to use a series of orbiting probes and a mothership to measure the gravity field of an asteroid or comet, and use this information to model the internal structure. Modelling the interior of small planetary bodies is something that we haven’t achieved yet as a species, simply because most of our exploration tools focus on large scale and surface features. We haven’t been able to put a drill hole into the centre of an asteroid yet!

Scientists are turning to remote sensing techniques like gravity, ground penetrating radar and radio tomography (think penetrating an asteroid with lightwaves of different frequencies and measuring the signal returning signal bouncing off different internal structures) to cheaply gather data on an asteroid’s interior.

In the above proposal the mothership will precisely monitor the position of the orbiters as they rotate the asteroid. Even a small change in orbit will reveal changes in density which can be caused by heavier or lighter material and empty spaces within. The combined data will be used to build a picture of the asteroid’s interior. This technique is already shown to be feasible through a series of simulations.

The benefits of such a project include the mothership being able to perform other experiments simultaneously, even leaving room to send a lander to the surface.

My only concern is in accurately tracking the position of the orbiters with respect to the asteroids surface. On Earth we need 4 GPS satellites to provide accurate location coordinates.

In other news, an incredible new photo reveals signs of geological features on Pluto, making a geophysicist like myself giddy with excitement. Even with a resolution of 27 kilometres, breathtaking new features can already be made out.

I think my reaction can be neatly summarised by this photo of science team members.

While it is unlikely that Pluto is still geologically active due to its small size, it seems apparent that it underwent a series of events leaving clues on its surface to its past.

As New Horizons principal investigator Alan Stern said, “After nine and a half years in flight, Pluto is well worth the wait.”

Different materials reflect various wavelengths of light in different proportions. As a result, each material has its own characteristic spectral signature.

Even with the most advanced telescopes, the light from distant planets beyond our solar system constitute a single pixel. This makes it hard to look for life, as the light signature from a planet gives us only the average of the near side of the planet.

Researchers from the University of Washington and the Virtual Planetary Laboratory published a paper in May in Astrobiology. They have found that if an organism with nonphotosynthetic pigments (which use light for things other than energy) cover enough of a planet’s surface, their influence on the spectral signature could be strong enough to be detected by a new generation of telescopes currently in development.

This possibility has been overlooked in previous searches for life, and while there are some difficulties with this method, it certainly broadens our ability to detect life at great distances.

A link to the original paper can be found here.

Until next time.

New Horizons – Journey to Pluto

After 9 years, only 5 days remain until New Horizons performs its flyby of Pluto!

Time to brush up on our (my) knowledge of this ex-planet.

“Did you know that until very recently, the best images we had of Pluto were just a few pixels in size? That’s right: those pictures you have in your head of what Pluto looks like are mere artists’ impressions.”

No!

During New Horizons’ close encounter we will see imagery revealing details as small as 50 metres across. For a sneak peak at what’s in store, check out this photo New Horizons took as it passed Jupiter.

Jupiter and Io taken by New Horizons in 2007 - image sourced from abc.net.au.
Jupiter and Io taken by New Horizons in 2007 – image sourced from commons.wikimedia.org.

New Horizons will pass as close as 12,500 km from Pluto, taking high resolution imagery as it floats by. It will take as long as 16 months to return 1 day worth of photos to Earth due to the probes’ low bandwidth!

I’m excited to see what insight we can get into the geology of Pluto with these images. Given how little we know about it, the little data we get from the imagery and New Horizons’ other equipment will surely yield some incredible discoveries!

Unfortunately, after Pluto, New Horizons is destined for a lonely journey through the Kuiper Belt, an icy ring of debris beyond Neptune. While there are millions of objects in this belt, they are few and far between, leaving New Horizons very unlikely to come into contact with one.

From there it will be on to the Oort cloud, and finally,  interstellar space.

For a more detailed summary of Pluto, check out this article by ABC News.

Until next time.

Rosetta and 67P

67P/Churyumov-Gerasimenko, named after its founders by the same names, is rapidly approaching its closest point in orbit to the Sun. At almost 38 km/s to be precise.

Comet 67P/Churyumov-Gerasimenko
Comet 67P/Churyumov-Gerasimenko. Image from wikimedia.commons.org.

Last November, the Rosetta spacecraft’s lander, Philae, became the man-made object to perform a soft landing on a comet.

And what a landing it was! Philae was unsuccessful at anchoring itself to the surface of the comet with its landing harpoons and bounced twice before coming to a halt in a dark zone. This was a problem as the lander couldn’t charge its batteries as well as planned using solar panels, and went into hibernation 3 days after touchdown.

Although Philae made contact at a very low speed, the low gravity on the comet (around one ten-thousandth that of Earth), meant that a small bounce was disastrous.

One proposed theory for the greater than expected ‘bounce factor’ is that the surface of 67P was elastic, with a hard crust under a metre thick overlying an elastic material (S. Ernst pers. comms.). This made me think of the recent announcement that the mysterious ‘craters’ on the surface are created when porous rocky material which has lost its water-ice due to outgassing. Eventually this porous rock can no longer hold its own weight, even in the low gravity of the comet (suggesting high porosity indeed… and a very high current or previous water content for the comet overall!), and it collapses, creating a sinkhole-like feature.

Perhaps the proposed ‘spongy material’ causing Philae to bounce is the same porous rock that is causing these sinkholes?

If so, is the whole surface of the comet poised on the brink of collapse with high porosity? Or did Philae get unlucky and land on a soon to be sinkhole?

These are the questions that excite me about space science. Part of my PhD will involve developing new and novel ways to test various models for the structure of asteroids and comets. Currently I’m looking at seismics and ground penetrating radar, but endless possibilities abound!

Until next time.

Edit: This article suggesting that 67P could be home to microbial life refers to an organic rich crust which is being constantly replenished. The presence of this crust and the replenishment of water (by outgassing from the deeper ice?) would support the above hypothesis!

Second edit: The Skeptics Guide to the Universe has stated that the original scientific research the above article was based on doesn’t actually make any claim to the existence of life on the comet. It just goes to show that one should always read the original science before commenting, as science journalism does get it wrong from time to time!

Getting started

Hi everyone!

My name is Michael Dello-Iacovo and I’m a geophysicist/soon to be asteroid mining PhD candidate at the University of New South Wales. I’m about to embark on an exciting journey and I want you to be a part of it!

Over the next 8 years I’m going to have some amazing times, and some trying times. Hopefully I’ll learn something and add to the incredible database of knowledge called science.

My research is focussing on developing exploration methods for mapping the interior structure and resources of asteroids and comets for extraction in the future. My primary focus will be on developing, simulating and testing seismic methods.

This website is for me to share my research while it’s in its early stages for feedback and hopefully your enjoyment. I’ll also be posting my travels to various conferences and field locations, and also talking about any new space science discovery I find exciting.

If you’re interested in collaborating or have any suggestions (you don’t need to be a scientist to have a great idea I mightn’t have thought of!) please do get into contact.

I’ll also be linking this blog to a Youtube channel at a later date, so stay tuned!

Until next time.