On December 11th, the NASA-led Artemis I mission came to a successful end after a 25-day journey to the Moon and back. The Orion capsule, which is designed to transport the crew of future Artemis missions, splashed down in the Pacific Ocean off the coast of Mexico. It is now being transported back to the Kennedy Space Centre in Florida so that NASA scientists can assess how well it performed throughout the mission.
Artemis I is being hailed as a series of successes. The Space Launch System (or SLS) rocket which launched the Orion capsule - together with its European-designed and built service module - into space performed exactly as intended. Considering that Artemis I was the first integrated flight of the SLS and the Orion capsule, this is no mean feat.
The spacecraft travelled over 1.4 million miles, completing two lunar flybys and coming within 80 miles of the lunar surface. At its farthest distance during the mission, Orion travelled nearly 270,000 miles from our home planet, more than 1,000 times further than where the International Space Station orbits the Earth. And during that time, numerous systems were checked and tested to ensure that the spacecraft can safely transport humans around the Moon - the intention of Artemis II, which is due to launch within the next two years.
Among the tests conducted was a modal survey, where NASA scientists conducted small ignitions of Orion's thrusters in order to ensure this didn't unduly flex the solar panel wings attached to the European service module.
Another test ensured the proper functioning of Orion's guidance, navigation and control system. The optical navigation camera which guides the system can help Orion autonomously return home if it were to lose communication with Earth. Meanwhile, scientists also tested cameras designed to check for micro-meteoroid or space debris strikes during the mission.
More experiments and tests came courtesy of a life-sized mannequin, nicknamed Commander Moonikin Campos, who was in the Orion capsule. One experiment concerns the levels of radiation future astronauts will be exposed to. Exposure will occur as the spacecraft travels through the Van Allen Belts (which contain radiation trapped around the Earth by its magnetic field), as well as from solar flares and cosmic rays.
Moonikin Campos is equipped with two radiation sensors, to see how protective an environment the capsule provides. Another key experiment concerns the acceleration and vibration forces future astronauts will experience. Crews are expected to experience up to four times the force of gravity during Artemis missions, so it's vital to understand whether this has been the case on Artemis I.
But perhaps the most dangerous and testing part of the mission was re-entry through the Earth's atmosphere. The Orion spacecraft separated from the service module in space. During re-entry, Orion endured temperatures about half as hot as the surface of the Sun at about 2800 degrees Celsius. Within about 20 minutes, Orion slowed from nearly 25,000 mph to about 20 mph for its parachute-assisted landing. Scientists will be carefully studying Orion's heat shield to ensure it performed as expected.
The tests and experiments conducted during Artemis I will be keeping scientists busy for months and years ahead as they prepare for the first crewed Artemis mission in 2024. For more detail on the future of Artemis, sign up for Mission Astro today - our in-depth interviews with key mission planners will be sure to inform and fascinate!
If you have any questions, please email course leader, Dr Sarah Crick, at sarah@justgoodscience.org
Dr Sarah Crick also offers bespoke tuition and master classes, so if you have a burning question about astrophysics then get in touch!
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It has been half a century since humans last walked on the Moon. But - in as little as three years' time - NASA's Artemis programme plans to return us there. Working in partnership with the European, Japanese and Canadian Space Agencies, the programme's long-term aim is to establish a permanent base on the Moon and - ultimately - to set the groundwork for human missions to Mars.
In this blog we'll explore the Artemis programme, in particular Artemis I, and understand more about what the coming years will look like.
On 16 November 2022, Artemis I launched from the Kennedy Space Center in Florida - hitting headlines around the world. This was the culmination of decades of work and technological development - much of which started during NASA's earlier Constellation programme.
Prior to Artemis I, NASA had been developing a new rocket for over a decade - building on the technology used to launch Space Shuttles. This resulted in the Space Launch System (SLS), which can carry the heaviest payload of any rocket currently in operational service.
Similarly, the Orion spacecraft - which sits on top of the SLS and will carry the astronauts all the way to the Moon - can trace its history back to the Constellation programme. It is made up of two parts - the Crew Module (which provides the habitat for the crew) and the European Service Module (which provides the in-space propulsion, water, oxygen and electrical power).
Artemis I is trailblazing in lots of ways. It saw the first attempt to launch the SLS rocket together with the Orion spacecraft. It's carrying three state of the art, astronaut-like mannequins to record the kinds of acceleration and vibration stresses that will come when humans fly to the Moon. It will test the radiation exposure that future astronauts will experience. And it will be the first real test of the Orion spacecraft's re-entry heat shields.
All of these firsts take place during a 25-day mission where the Orion spacecraft will fly by the Moon twice - coming within approximately 62 miles of the lunar surface, and travelling 280,000 miles from the Earth. The science will have only just begun once Artemis I splashes down in the Pacific Ocean. Attention will inevitably then turn to the first human-crewed mission - Artemis II - which is currently planned for launch in 2024.
Artemis II will see humans fly by the Moon for the first time in over 50 years. Artemis III - scheduled for launch in 2024-5 - will see two astronauts spending a week on the lunar surface, the first such landing since Apollo 17 in 1972. And Artemis missions further in the future will see major developments of the lunar Gateway – a space station in orbit around the Moon – to facilitate future landings. In short, there is an exciting and challenging programme of work which will take us well into the next decade.
If you want to hear more about the future of the Artemis programme then why not listen to Mission Astro's interview with Dr Natasha Almeida of the Natural History Museum? You'll hear more about the colossal effort that's being put into the Artemis missions - including mapping landing sites, exciting science on the origin of water in our Solar System and the many new technologies being developed.
This is just one of many in-depth expert interviews you can access as part of Mission Astro. Sign up today - we'll take you on an exciting ride through the cosmos and you're sure to learn a lot along the way!
We even have a free taster session on supermassive black holes and the stars that fall into them! If you have any questions, please email course leader, Dr Sarah Crick, at sarah@justgoodscience.org
Dr Sarah Crick also offers bespoke tuition and master classes, so if you have a burning question about astrophysics then get in touch!
Take me to the FREE taster session for Mission Astro!
Space contains some of the most fascinating and exotic objects ever studied! From black holes to pulsars, exoplanets to supernovas, the cosmos is teeming with bodies which stretch our imaginations and our understanding of how the universe works. For the past 30 years or so, many of the most incredible discoveries humankind has made have come from the Hubble Space Telescope.
In this blog we look at the key differences between these two magnificent telescopes and discover how they both play an incredibly important part in research.
Hubble's track record is impressive. In 1994, Hubble provided conclusive evidence of the existence of supermassive black holes at the centres of galaxies by observing the galaxy M87. In 2001, Hubble measured the elements in the atmosphere of exoplanet 209458b - the first planetary atmosphere outside the Solar System to be detected. And in 2010, Hubble photographed never-before-seen evidence of a collision between two asteroids.
And Hubble still has plenty left to give. Despite being operational for over three decades and having a relatively modest 2.4m mirror, demand for its use in research still exceeds available observing time. It remains unbeaten in its ability to observe the universe at the optical and ultraviolet wavelengths.
A large part of its success comes from the fact that it is in space. This gives Hubble two distinct advantages over bigger 8-10m Earth-based telescopes. Firstly, it means that Hubble can capture observations without being affected by the air currents that appear to make stars twinkle from the ground. And secondly, it can observe in the ultraviolet wavelength - which is all but impossible from the ground given the presence of gases such as ozone in the atmosphere, which blocks ultraviolet light.
While these advantages mean Hubble still has at least ten to twenty more years before it's retired, plans for the next generation of space telescope began as long ago as 1996. Decades of work were put in, culminating in the launch - on Christmas Day 2021 - of the James Webb Space Telescope (JWST). A combined project with the European Space Agency and the Canadian Space Agency, JWST has enough fuel to last at least the next ten years.
Early observations from JWST have been spectacular. There's a continued focus on exoplanets with observations of the atmospheric composition of the hot gas giant WASP-96b. There are images of enormous gas clouds which are the nurseries in which new stars are born. And there are observations of the composition of very distant galaxies, some 13.1 billion light-years away. And this is in the first few months of observation time.
JWST is different from Hubble in several key ways. For a start, JWST's mirror is 6.5m in size - two and a half times bigger than Hubble's. Hubble is in a near-Earth orbit, whereas JWST is 1.5 million kilometres away. And JWST observes at the infrared end of the electromagnetic spectrum, whereas Hubble primarily observes the visible and ultraviolet.
It is this focus on the infrared which really differentiates the two. A core part of JWST's mission is to look at some of the most distant galaxies in the universe. More distant objects are more highly red-shifted and their light is moved from the ultraviolet and optical to the infrared. Combined with its bigger mirror, this means JWST will be able to peer further back in time than Hubble and help to answer more questions about the early universe.
If you want to learn more about some of the fascinating objects mentioned in this blog, then sign up to Mission Astro today! With 32 sessions covering a range of objects and phenomena observed across the Milky Way, you're sure to learn so much about the cosmos.
We even have a free taster session on supermassive black holes and the stars that fall into them! If you have any questions, please email course leader, Dr Sarah Crick, at sarah@justgoodscience.org
Dr Sarah Crick also offers bespoke tuition and master classes, so if you have a burning question about astrophysics then get in touch!
Take me to the FREE taster session for Mission Astro!
We all know how the nursery rhyme goes and we all see that stars ‘twinkle’ if we catch a glimpse of them on a clear night, but do the stars themselves actually twinkle?
Distant stars appear to twinkle when we observe them from Earth. This is because the stars are so far away that when their light arrives here, it covers such a small area on the sky that it appears as a single point of light. When this light travels through the atmosphere, it’s direction is changed by the atmosphere itself making its path a random zig-zag rather than it’s usual direct path. This creates the famous twinkling effect that we see. The more atmosphere a star passes through, the more twinkly it appears. So, rather boringly, stars do not actually twinkle.
In short, no! Some of them do change brightness before our eyes and these stars are actually very important in Astronomy. They are called variable stars because their magnitude varies with time. One example of a variable star is called a Cepheid variable. These stars themselves expand and contract in regular patterns. Their change in magnitude is all linked to their changing size and surface temperature. These stars are more massive than our Sun and they are in an unstable part of their lives while pulsating as Cepheids. They are very luminous and easy to spot in this stage. There is a well-known establish relationship between the time between maxima of these stars and their actual intrinsic brightness. This is a major tool for astronomers to work out distances to objects. Cepheid variables can be observed both in our Galaxy and others, therefore if we know how long it is between 'flashes' we can use that to determine it’s actual absolute magnitude. If we compare that to its apparent magnitude as observed from Earth, we can work out how far away other Galaxies are using a formula. How useful is that?!
So in conclusion, no twinkling but definitely some 'flashing'!