Tag: Spaceflight

2019 marks the 50th anniversary of human beings setting foot on the surface of our Moon. The Apollo programme may have first and foremost been driven out of political need / desires, but it nevertheless stands as a remarkable achievement, given it came n the same decade when a human being first flew in space, and a little under 12 years since the very first satellite orbited the Earth.

To this day, Apollo stands as one of the most remarkable space programmes ever witnessed in terms of scale, cost, and return. It propelled a generation of American school children to pursue careers in engineering, flight, the sciences and more. In all, the Apollo lunar programme flew a total of 11 crews in space between 1967 and 1972, nine of them to the Moon, with two crewed missions to Earth orbit.

After the tragedy of the Apollo 1 fire in January 1967, which claimed the lives of Virgil “Gus” Grissom, Edward White II and Roger B. Chaffee, NASA worked hard to redesign the Apollo Command Module, providing far greater insulation against the risk of fire, as well as altering the vehicle’s atmosphere (from 100% oxygen to a 60/40 oxygen / nitrogen mix) and altering the main hatch so that the crew could escape in the event of a launch pad emergency. In October 1968, the redesigned vehicle, along with its supporting Service Module (together referred to as the Command and Service Module, or CSM) was tested in Earth orbit for the first time by the crew of Apollo 7.

Scheduled for launch towards the end of 1968, Apollo 8 had originally been planned as the first orbital flight test of the CSM and Lunar Module (LM). However, two events encouraged NASA to revisit their plans. Due to continued delays in the delivery of a flight-ready LM, the agency decided to swap the Apollo 8 and Apollo 9 missions and crews around; Apollo 9 would flight-test CSM and LM, once available. Meanwhile, Apollo 8, carrying Frank Borman, Jim Lovell and Bill Anders, and marking the first crewed flight of the mighty Saturn V rocket, would be used in an orbital flight designed to simulate the atmospheric re-entry at the speeds a Command Module would face on a return from the Moon without actually sending the crew to the Moon.

Then, in August and September 1969 photographs captured by US spy satellites suggested the Soviet Union had one of its massive N1 rocket, easily the equal of Saturn V, sitting on a launch pad. With fears that the Soviet Union was perhaps approaching the point where it could launch a crewed mission to the Moon, Apollo 8 was further revised and Borman, Lovell and Anders were informed they’d be spending Christmas 1968 where no other person had spent Christmas before: in orbit around the Moon, allowing them to fully check-out the CSM as it would be flown in an actual lunar landing mission.

So it was that on Saturday, December 21st, 1968, Borman, Lovell and Anders were strapped into their seats atop the 110.6 metre (363 ft) tall Saturn V, about to undertake the longest journey ever undertaken by humans up until that point in time. At 07:51 local time (12:51 UTC) the five massive F-5 engines of the rocket’s first stage thundered into life, slowly lifting the 2,812 tonne (US 3,100 short tons) vehicle into the sky.

On reaching orbit, the CSM still attached to the Saturn V’s third stage, spent some 2 hours and 30 minutes in orbit while the crew performed a final check of their systems. Then the S-IVB motor was re-started, and in five minutes accelerated the vehicle from 7,600 to 10,800 metres per second (25,000 to 35,000 ft/s), pushing it away from Earth and on course for the Moon. With TLI – Trans-Lunar Injection successfully completed, the crew separated the CSM and rotated it to photograph the expended third stage, still following behind.

After a mid-course correction, and around 55 hours and 40 minutes after launch, the crew of Apollo 8 became the first humans to enter the gravitational sphere of influence of another celestial body as the effect of the Moon’s gravitational force on the vehicle had become stronger than that of the Earth. Nine hours later, the crew performed the second of two mid-course corrections using the CSM’s reaction control system, bringing them to within 115.4 km (71.7 m) of the lunar surface and oriented ready for a burn of the Service Module’s main motor to slow them into lunar orbit.

Continue reading “Space Sunday: recalling Apollo 8” →

It’s been a further busy week for NASA’s InSight Lander as it starts to get down to business. In particular, the rover has been further exercising its robot arm and preparing for the start of operations – work that has involved surveying its local surroundings.

The week started with NASA releasing InSight’s first “selfie”, a mosaic of 11 images captured by the Instrument Deployment Camera (IDC), located on the elbow of the lander’s robotic arm. Clearly visible in the completed image is the copper-coloured seismometer that will be placed on the surface of Mars to listen to the planet’s interior with its silver protective dome just behind it. Also visible is the black boom of the robot arm rising mast-like.

The IDC is one of two camera systems on InSight, but the only one that is fully mobile. It will be used in conjunction with the Instrument Context Camera (ICC), fixed to the lander’s hull, to correctly place the surface instruments of the SEIS seismometer and the HP3 drilling mechanism on Mars.

The static nature of the ICC means that placement of the surface instruments is limited to an arc directly in front of the lander, and as well as taking selfies, InSight has been using the IDC to survey this area from above.

Deployment of these two instruments will take time. While operations will start in the coming week, they will likely take around two months to complete. The SEIS will be deployed first. This will be a complex task, placing the unit on the surface first, followed by its protective cover, designed to prevent the Martian wind and atmospheric changes affecting the readings the seismometer takes of the planet’s interior.

If all goes according to plan, the HP3 will be deployed in around mid-January. It will commence operations as soon as possible after deployment. However, it will be an extended process before the instrument starts to deliver on its science goals. This is because the self-hammering heat probe within HP3 – nicknamed the mole – has to “drill” its way some 5 metres (16ft) below the Martian surface. However, it will take time because the probe must pause periodically to release a burst of heat that will help it determine the nature of the material around it and possible hazards below it.

They were speaking about the seven minutes of terror on landing, now I’m saying we have two months of terror in front of us when we penetrate into the surface. The drilling mechanism relies on pushing aside dirt. Smaller rocks it can either push aside or burrow around, but a large rock – 1 metre [3ft] in diameter or so – would stymie the probe’s drilling mechanism. 

– Tilman Spohn, of the German space agency DLR, and HP3’s principal investigator

In particular, the effectiveness of HP3 depends on how deeply it penetrates the regolith.

The less we penetrate, the worse it will be. If it’s just 1 m (3 ft) or so deep, the team will need to rely on more intensive modelling. But if it reaches 3 m (10 ft), which should occur around mid February, the team will be pleased — and if it can reach the full depth of 5 m (16 ft) around March 10th or so, all the better.

– Tilman Spohn

The survey of the landing site has helped confirmed that despite early misgivings when InSight first touched-down, the area occupied by the lander is about as free from rocks and possible surface hazards for SEIS and HP3 as might have been possible to find.

Virgin Galactic Reaches Space with VSS Unity

On December 13th, 2018, Virgin Galactic carried out a supersonic flight test that carried VSS Unity into space for the first time – at least according the NASA’s and the US Air Force’s reckoning. The success of the flight takes Virgin Galactic closer to taking paying customers on the six-passenger rocketplane, which is about the size of an executive jet, on sub-orbital flights into space.

Unity, also referred to as SpaceShipTwo, was carried aloft by its mothership, WhiteKnightTwo from the Mojave Space Port to an altitude of 13,100 metres (43,000 feet). It was then dropped from the carrier jet, allowing the crew of two, Mark “Forger” Stucky and former NASA astronaut Rick “CJ” Sturckow, to ignite the single rocket motor. Burning for 60 seconds,  the motor allowed Unity to start a rapid climb and achieved Mach 2.9, nearly three times the speed of sound.

After engine cut-out, the vehicle continued to climb for a further minute, reaching an altitude of 82 km (51 miles) – enough to put it across the line NASA and the US air Force consider to be the edge of space relative to Earth (80 km / 50 mi above sea level).

Once Unity reached apogee, the two pilots were afforded some brief moments of microgravity. They then “feathered” the tail booms, causing the vehicle to gently fall back into the denser atmosphere like a shuttlecock. Once air density was sufficient, the tail sections returned to their “regular” position, allowing the vehicle to achieve unpowered aerodynamic flight, landing back at Mojave Air and Space Port at 08:14 local time (16.14 UTC), with the flight from the drop to the landing lasting 14 minutes in total.

While NASA and the US Air Force view the edge of space being at 80 km, the Fédération Aéronautique Internationale (FAI), the international standard-setting and record-keeping body for aeronautics and astronautics, officially place the boundary between atmosphere and space – called the Kármán line – at 100 km (62 mi; 330,000 ft). Nevertheless, the flight is enough for Stucky to gain his astronaut wings, and for Virgin Galactic to talk in terms of commencing passenger-carrying operations in the near future.

Continue reading “Space Sunday: InSight, space and interstellar space” →

It’s always a remarkable time when a new mission arrives on or around another planet in our solar system, so forgive me if I once again kick-off a Space Sunday with NASA’s Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) lander, which touched down on Mars just 10 days ago.

Over the course of the last several days, NASA has been putting the lander’s 1.8 metre (6 ft) long robot arm through its paces in readiness for operations to commence. The arm has multiple functions to perform, the most important of which is to place two major science experiments on the surface of Mars. The arm is also home to one of the two camera systems on the Lander.

Very similar to the Navcam systems used by both Opportunity and Curiosity, the camera is called the Instrument Deployment Camera (IDC). It is mounted above the arm’s “elbow” and has a 45-degree field of view. As well as offering a first-hand view of everything the robot arm is doing, IDC can provide colour, panoramic views of the terrain surrounding the landing site.

The arm hasn’t as yet been fully deployed, but in being put through its paces, it has allowed the IDC to obtain some tantalising views of both the lander and its surroundings.

Some powering-up of science systems has also occurred, notably Auxiliary Payload Sensor Systems (APSS) suite. The air pressure sensors immediately started recording changes in air pressure across the lander’s deck indicative of a wind passing over InSight at around 5 to 7 metres a second (10-15mph). However, the biggest surprise can from the seismometer designed to listen to the interior of Mars.

As this was tested, it started recording a low-frequency vibration in time with the wind recordings from APSS. These proved to be the wind blowing over the twin 2.2-metre circular solar panels, moving their segments slightly, causing the vibrations, which created a sound at the very edge of human hearing. NASA later issued recordings of the sounds, some of which were adjusted in frequency to allow humans to more naturally “hear” the Martian wind.

The InSight lander acts like a giant ear. The solar panels on the lander’s sides respond to pressure fluctuations of the wind. It’s like InSight is cupping its ears and hearing the Mars wind beating on it.

– Tom Pike, InSight science team member, Imperial College London

Once on the surface of Mars and beneath its protective dome, the seismometer will no longer be able to hear the wind – but it will hear the sound of whatever might be happening deep within Mars. So this is likely to be the first of many remarkable results from this mission.

To Touch an Asteroid

NASA’s OSIRIS-REx (standing for Origins, Spectral Interpretation, Resource Identification, Security – Regolith Explorer), launched in September 2016, has arrived at its science destination, the near-Earth asteroid Bennu, after a journey of two billion kilometres.  It will soon start a detailed survey of the asteroid that will last around  year.

Bennu, which is approximately 492 m (1,614 ft) in diameter, is classified as a near-Earth object (NEO), meaning it occupies an orbit around the Sun that periodically crosses the orbit of Earth. Current orbital predictions suggest it might collide with Earth towards the end of the 22nd Century.

To this end, OSIRIS-REx will analyse the thermal absorption and emissions of the asteroid and how they affect its orbit. This data should help scientists to more accurately calculate where and when Bennu’s orbit will intersect Earth’s, and thus determine the likelihood of any collision. It could also be used to better predict the orbits of other near-Earth asteroids.

Bennu is primarily comprised of carbonaceous material, a key element in organic molecules necessary for life, as well as being representative of matter from before the formation of Earth. Organic molecules, such as amino acids, have previously been found in meteorite and comet samples, indicating that some ingredients necessary for life can be naturally synthesized in outer space. So, by gaining samples of Bennu for analysis, we could answer many questions on how life may have arisen in our solar system – and OSIRIS-REx will attempt to do just that.

Towards the end of the primary mission, OSIRIS-REx will be instructed to slowly close on a pre-selected location on the asteroid, allowing a “touch and go” sampling arm make contact with the surface for around 5 seconds. During that moment, a burst of nitrogen gas will be fired, hopefully dislodging dust and rock fragments, which can be caught by the sampling mechanism. Up to three such sample “hops” will be made in the hope that OSIRIS-REx will gather between 60 and 2000 grams (2–70 ounces) of material. Then, as its departure window opens in March 2021, OSIRIS-REx will attempt a 30-month voyage back to Earth to deliver the samples for study here.

Continue reading “Space Sunday: hearing Mars, looking at Bennu and roving the Moon” →

On Monday, November 26th, 2018, the latest in a series of NASA missions, the InSight lander – built with international cooperation -, arrived on the surface of Mars.

As noted in my previous Space Sunday report, confirmation that InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) had safely arrived could only be received by mission control at NASA’s Jet Propulsion Laboratory (JPL) after the team there had endured the “seven minutes of terror”, more officially known as the Entry, Descent and Landing (EDL) phase of its journey, the time when the vehicle would enter Mars’ atmosphere and hopefully make a reasonably soft-landing on the planet’s surface.

While undeniably tense, when it came to it – and watched live via social media,  and assorted web broadcast channels put out by NASA – EDL was completed flawlessly. After separating from is cruise element around 7 minutes prior to EDL, InSight, protected by its heat shield and aeroshell, entered the upper reaches of the Martian atmosphere almost precisely on schedule, where over a 4-minute period, the frictional heat created by is passage helped decelerate it from an initial entry velocity of 19,800 km/h (12,300 mph) to 1,400 km/h (860 mph). At this point, telemetry once again being relayed, the supersonic braking parachute was been deployed.

After this things moved quickly: the heat shield was jettisoned from under the lander, which itself dropped free of the parachute and conical aeroshell, using its 16 rocket motors to achieve a “soft” landing on the surface of Mars – travelling at just 8 km/h (5 mph). A video compressing the seven minutes into just over a minute and a half captures the landing – and the joy at mission control (not the celebratory handshake at 1:19!).

It had been anticipated that the first “official” confirmation that InSight had arrived safely would be a “beep” sent directly to Earth from the lander’s X-band radio – and this might be followed a few minutes later by a photograph taken by the lander. As it turned out, and thanks to two tiny CubeSats – of which  more in a moment – it was the photo that arrived first. Grainy and indistinct due to it being taken by a camera still with its protected lens cap in place (itself splattered with dust), it shows a rocky surface and a tightly curved horizon – caused by the camera still being in its stowed configuration.

Initially after landing, InSight was operating on battery power whilst awaiting the dust to settle out of the atmosphere so the two circular solar panels could be deployed. This occurred some 30 minutes after touchdown, with the panels proving so efficient that . So efficient are these panels that during their Martian Sol of operation, they set a new record for power generation: 4,588 watt-hours – well over the 2,806 watt-hours generated in a single Sol by the “nuclear powered” Curiosity.

The efficiency of InSight’s solar arrays will deteriorate over time – the result of general wear-and-tear and the influence of dust that will inevitably accumulate on them – but the power levels have been more than enough for the lander to start flexing its muscles – including testing its robot arm, which is essential to it being able to place key experiments on the surface on Mars.

It is going to be early spring 2019 before InSight is fully involved in its science mission. There are a lot of equipment check-outs and calibration test to be undertaken, as well as the surface deployment of key instruments. However, there have been some external concerns raised over how well InSight will fulfil its science objectives. As data started coming back from the lander, it was noted that it had touched down in a shallow impact crater, almost completely filled by sand and dust (such craters being known as “hollows” on Mars), which has given InSight a 4-degree tilt.

Overall, the lander can in theory operate with up to a 15-dgree cant (the result of one of this three landing legs coming down on a boulder, for example), but here is a worry about how the tilt may impact placing the Seismic Experiment for Interior Structure (SEIS) and HP3, the Heat Flow and Physical Properties Package, on the surface of Mars, and how the material filling the hollow might affect the operation of HP3’s “mole”, which is designed to burrow into subsurface rock and measure the heat flow from the centre of the planet.

Nevertheless the mission team remain in a positive mood and are delighted with both the landing and the first few days of operations.

We couldn’t be happier. There are no landing pads or runways on Mars, so coming down in an area that is basically a large sandbox without any large rocks should make instrument deployment easier and provide a great place for our mole to start burrowing.

– InSight project manager Tom Hoffman

Further examination of the lander’s surroundings will be made once the dust covers have been ejected from the on-board cameras, something that should happen in the next few days. This work will include a careful study of the ground to determine the best placement for SEIS and HP3, as well as a general surveying of the location, which in the initial images, appears a lot less rock-strewn than other locations visited by landers and rovers.

We are looking forward to higher-definition pictures to confirm this preliminary assessment. If these few images—with resolution-reducing dust covers on—are accurate, it bodes well for both instrument deployment.

– Bruce Banerdt, InSight principal investigator

I’ll have more on InSight as the mission develops.

Continue reading “Space Sunday: InSight, MarCO and privately to the Moon” →