Day: March 29, 2021

If all goes according to plan, on Thursday, April 8th, we could be witnessing the first powered flight of an aerial vehicle on another planet as the blocky Ingenuity helicopter, part of NASA’s Mars 2020 mission, takes to the air for the first of what should be at least five proof-of-concept flights.

The helicopter itself is not a particularly exciting thing to look at: a cube-like fuselage no more than 20 cm across on its longest side that contains the vehicle’s avionics, a heater system to keep the sensitive circuitry warm and operating, a battery system to provide energy to the headers and the vehicle’s propellers, and its science systems. It is supported by four spindly legs just 38 cm long, and is topped by a mechanism of two contra-rotating co-axial rotor systems measuring 1.2 metres from tip-to-tip, with the main communications antennae above them, topped by the solar panels hat will be used to recharge the vehicle’s batteries.

However, looks can be deceptive. Ingenuity is actually a highly capable aircraft and spacecraft combined. Its systems were designed to withstand 6+ months of interplanetary space travel , while its flight systems have been designed to get it into the air on  a planet where the atmosphere is only about ​¹⁄₁₀₀ as dense as Earth’s.

To put that in perspective: Ingenuity will be attempting to lift off in an atmospheric density that matches our own at 30,000 metres  – that’s almost four times the height of Mount Everest and a height well beyond the capabilities of any Earthbound helicopter. And where the lower gravity of Mars means Ingenuity ways just one third as much as it does when measured on Earth, this offers little in the way of compensation for the rarefied atmosphere.

Hence why Ingenuity is a proof-of-concept vehicle: just getting aloft with be a tremendous achievement – but if it can be shown to do so repeatedly, and to manoeuvre successfully, it could dramatically alter future robotic and human missions to Mars by providing  aerial support for them as terrain scouts or standalone science vehicles carrying their own payloads  operating remotely or – in the case of human missions – flown drone-like from a base of operations.

The first phase of operations for the mission was for Perseverance to scout the land close to its landing point – Octavia E. Butler Landing – to  find a suitable area of level ground over which Ingenuity can fly. This required finding an area some 90 metres in length and roughly 12-15 metres wide relatively clear of significant obstacles that might limit landing options., and with an area 10 metres on a side from which the first flight will be made and which has been dubbed “the airfield”. 

This deployment requires a number of actions to occur, the first of which came on Sunday, March 21st, when the cover that had been protecting Ingenuity was dropped from under the rover (see my previous Space Sunday update). Once Perseverance is correctly positioned at the centre of “the airfield”, the rest of the deployment will take place over a period of 6 Martian sols (days):

• Sol 1: restraining bolts locking Ingenuity in place under the rover will be released.
• Sols 2 and 3: a cable also holding the helicopter will be explosively released, triggering a motor that will gently rotate the helicopter down into an upright position beneath the rover, allowing two of Ingenuity’s landing legs to spring into their deployed position in the process.
• Sol 4: the remaining two legs on Ingenuity will be released to snap into place. At this point, the helicopter will be slung under the rover, held in place by a single bolt and a set of power connectors.
• Sol 5: Perseverance will carry out a full charge cycle of Ingenuity’s batteries – until now, the rover has only charged the batteries to around one-third their capacity, enough to keep the helicopter’s system warm.
• Sol 6: The rover will be commanded to release the helicopter, allowing it to drop the 13 centimetres to the ground.

At this point, things will get a little risky: there will be no means to communicate with the helicopter, and its batteries can only supply it with power for 25 hours without recharge. In this time, a final visual check on Ingenuity must be carried out using the WATSON imager on  the rover’s robot arm, and then the rover must carefully reverse away from the helicopter to a distance of 5 metres.

Once at this distance, the rover will be able to act as a communications relay between mission control and the helicopter, allowing mission control to command the helicopter to switch to charging its batteries from its solar cells and upload the required flight software.

In all, the flight team have 30 days from the moment Ingenuity is released from Perseverance to complete the planned five flights. After this time, the rover must commence its own science programme. The flight team will therefore be looking to complete those five flights in as short a space of time as possible. For the first flight, Ingenuity will do little more than attempt to rise to a height of 3 metres, hover for 30 seconds and then land safely. After this, the remaining four flights will be for longer and to heights of around 5 metres, and for increasing distances down “the airfield”.

If we get past those [flights], we will assess:  did we meet all our objectives during those flights? Do we want to go back and retry some of those things? Or, if everything goes really well, then we might try to stretch our capabilities beyond those basic capabilities.    

– Ingenuity chief pilot Håvard Grip

All of the flights will hopefully be documented by Perseverance its powerful Mastcam-Z camera system and two on-board microphones from an observation point some 60 metres from “the airfield”, which it will drive to prior to the first flight.

This observation point has been dubbed the Van Zyl Overlook in honour of key Ingenuity team member Jakob van Zyl, the former director for solar system exploration and associate director for project formulation and strategy at NASA’s Jet Propulsion Laboratory, who passed away unexpectedly in August 2020.

When it makes its flights, Ingenuity will both make history and carry a piece of history with it: attached to the Helicopter is a small piece of fabric taken from the Wright Brother’s 1903 biplane, credited with making the he first powered, controlled flight on Earth on December 17th, 1903.

‘Oumuamua is Likely a Piece of a Planet

In 2017 the Pan-STARRS astronomical observatory in Hawaii identified an object of extra-solar origin on a course that would carry it around the Sun. Named  ‘Oumuamua, meaning “scout” or “messenger” in Hawaiian, it was the first such object to be positively identified as coming from beyond the solar system,  although it is now believed that as many as five such object could pass through the solar system every year.

‘Oumuamua, however, was not only the first to be positively identified, it was also highly unusual – so much so that it couldn’t be classified as either an asteroid or a comet, as it exhibited behaviour common to both – and behaviour and attributes not found in either. This has lead to a variety of possible theories being put forward for it might be – up to and including the idea it was actually an interstellar probe created by an alien intelligence.

However, two astrophysicists from Arizona State University believe they now have solved the mystery of ‘Oumuamua.Taking the more comet-like behaviours of the object, Steven Desch and Alan Jackson started looking for combinations of ices and volatiles that, when affected by the heat of the Sun, who produce the kind of reactions seen with ‘Oumuamua.

Their research lead them to a combination of nitrogen-dominant ices that, under computer modelling, not only produced the kind of non-tail generating outgassing seen with ‘Oumuamua, they they closely match combinations of nitrogen, methane and other ices found on Pluto and Neptune’s moon Triton.

These findings, coupled with further computer modelling, tend to suggest ‘Oumuamua  is likely a part of a Pluto-like planet orbiting a star somewhere in our stellar neighbourhood (separate estimates of data gathered on the object suggest it is around a billion years old, so must has originated fairly close to us, given its observed velocity through the solar system). If correct, then Densch and Jackson may not only have solved the nature of ‘Oumuamua , they may have shown that a new class of exo-planets exists: so-called “exo-Plutos”.

Continue reading “Space Sunday: getting ready to fly on Mars” →