Hidden in one of the darkest corners of the Orion constellation, this Cosmic Bat is spreading its hazy wings through interstellar space two thousand light-years away. It is illuminated by the young stars nestled in its core — despite being shrouded by opaque clouds of dust, their bright rays still illuminate the nebula. Too dim to be discerned by the naked eye, NGC 1788 reveals its soft colours to ESO’s Very Large Telescope in this image — the most detailed to date.
ESO’s Very Large Telescope (VLT) has caught a glimpse of an ethereal nebula hidden away in the darkest corners of the constellation of Orion (The Hunter) — NGC 1788, nicknamed the Cosmic Bat. This bat-shaped reflection nebula doesn’t emit light — instead it is illuminated by a cluster of young stars in its core, only dimly visible through the clouds of dust. Scientific instruments have come a long way since NGC 1788 was first described, and this image taken by the VLT is the most detailed portrait of this nebula ever taken.
Even though this ghostly nebula in Orion appears to be isolated from other cosmic objects, astronomers believe that it was shaped by powerful stellar winds from the massive stars beyond it. These streams of scorching plasma are thrown from a star’s upper atmosphere at incredible speeds, shaping the clouds secluding the Cosmic Bat’s nascent stars.
NGC 1788 was first described by the German–British astronomer William Herschel, who included it in a catalogue that later served as the basis for one of the most significant collections of deep-sky objects, the New General Catalogue (NGC) . A nice image of this small and dim nebula had already been captured by the MPG/ESO 2.2-metre telescope at ESO’s La Silla Observatory, but this newly observed scene leaves it in the proverbial dust. Frozen in flight, the minute details of this Cosmic Bat’s dusty wings were imaged for the twentieth anniversary of one of ESO’s most versatile instruments, the FOcal Reducer and low dispersion Spectrograph 2 (FORS2).
FORS2 is an instrument mounted on Antu, one of the VLT’s 8.2-metre Unit Telescopes at the Paranal Observatory, and its ability to image large areas of the sky in exceptional detail has made it a coveted member of ESO’s fleet of cutting-edge scientific instruments. Since its first light 20 years ago, FORS2 has become known as “the Swiss army knife of instruments”. This moniker originates from its uniquely broad set of functions . FORS2’s versatility extends beyond purely scientific uses — its ability to capture beautiful high-quality images like this makes it a particularly useful tool for public outreach.
This image was taken as part of ESO’s Cosmic Gems programme, an outreach initiative that uses ESO telescopes to produce images of interesting, intriguing or visually attractive objects for the purposes of education and public outreach. The programme makes use of telescope time that cannot be used for science observations, and — with the help of FORS2 — produces breathtaking images of some of the most striking objects in the night sky, such as this intricate reflection nebula. In case the data collected could be useful for future scientific purposes, these observations are saved and made available to astronomers through the ESO Science Archive.
 In 1864 John Herschel published the General Catalogue of Nebulae and Clusters, which built on extensive catalogues and contained entries for more than five thousand intriguing deep-sky objects. Twenty-four years later, this catalogue was expanded by John Louis Emil Dreyer and published as the New General Catalogue of Nebulae and Clusters of Stars (NGC), a comprehensive collection of stunning deep-sky objects.
 In addition to being able to image large areas of the sky with precision, FORS2 can also measure the spectra of multiple objects in the night sky and analyse the polarisation of their light. Data from FORS2 are the basis of over 100 scientific studies published every year.
ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It has 16 Member States: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Ireland, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile and with Australia as a Strategic Partner. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its world-leading Very Large Telescope Interferometer as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. Also at Paranal ESO will host and operate the Cherenkov Telescope Array South, the world’s largest and most sensitive gamma-ray observatory. ESO is also a major partner in two facilities on Chajnantor, APEX and ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre Extremely Large Telescope, the ELT, which will become “the world’s biggest eye on the sky”.
ESA: Review board gives JUICE the all clear
ESA’s JUpiter ICy moons Explorer, JUICE, has been given the green light for full development after its critical design review was successfully concluded on 4 March. This major milestone marks the beginning of the qualification and production phase, taking this flagship mission one key step closer to starting its long journey to Jupiter in 2022.
The critical design review (CDR) was carried out during the period between December 2018 and March 2019, although preparations for this major review began many months earlier.
Around 100 people from ESA were involved in the CDR, including the members of the review board, chairpersons, reviewers, and project team members. The review also required a major effort and investment from all parties involved, including industrial partners.
In preparation for the review, five independent CDRs were held for main JUICE subsystems as well as 14 equipment CDRs, with over 400 documents were delivered to ESA by the start of the review.
Meanwhile, the review teams themselves were divided into dedicated panels that would each focus on specific aspects of the design: mission/system; mechanical/thermal; product assurance/quality/safety; electrical; assembly, integration, and testing; and schedule.
On 4 March, the review board declared the JUICE CDR a success, meaning no obstacle has been identified that should prevent the mission from moving to the qualification and production phase. The review confirmed that the project is under control and that the design as reviewed is expected to meet the science and mission requirements.
“JUICE is half way through its development programme and running precisely on schedule,” said Giuseppe Sarri, ESA’s JUICE project manager. “The excellent outcome of the critical design review, with a clear and confirmed design, gives confidence that the planned launch date will be met.”
After launch, currently planned for 2022, JUICE will embark on a 7.5-year cruise toward Jupiter, entering orbit around the giant planet in 2029 to study its environment and three of its icy moons: Ganymede, Europa and Callisto.
“The critical design review was a long time in preparation, but the preparation itself proved very useful to consolidate the mission’s status after a few years of rapid progress since the preliminary design review,” added Robert Furnell, ESA’s JUICE system engineering manager.
“The result is evidence that all the teams are working well and that the design is secure. The critical design review was held as planned, almost exactly two years after the preliminary design review, demonstrating that the project remains on course for launch in 2022.”
Reviews of the mission’s science capabilities were all positive. They found that the communications downlink capability from the spacecraft exceeds requirements. The power and energy available for supporting the payload operations provides sufficient margins for the flybys of Europa in particular.
Overall, the pointing performances of the spacecraft and its trajectory in the Jupiter system also meet the mission requirements. The propellant budget is adequate to perform the required mission.
Furthermore, the primary science operations, which involve a series of Europa flybys and insertion into a 500-km circular orbit around Ganymede, have been validated by industry.
“The critical design review has shown that we are on the right track with this fantastic mission,” said Olivier Witasse, ESA’s JUICE project scientist. “We are well on the way to developing a spacecraft that will provide the most complete exploration of the Jupiter system, and characterise the subsurface oceans inside the planet’s giant icy moons.”
In the next phase, the JUICE team will start to integrate and test the flight model version of the spacecraft, starting with the structure and chemical propulsion system.
In parallel with integration of the flight model, testing will continue on the electrical and functional engineering model spacecraft mockup in Toulouse, France, whichis currently outfitted with key units from the platform and instrument packages.
The next major milestone for JUICE will be the flight acceptance review, currently scheduled for late 2021, which will declare whether the spacecraft is ready for launch.
JUICE (JUpiter ICy moons Explorer) is the first large-class mission in ESA’s Cosmic Vision 2015-2025 programme. It will complete a unique tour of the Jupiter system that will include in-depth studies of three potentially ocean-bearing satellites, Ganymede, Europa and Callisto.
The Jupiter tour includes several flybys of each planet-sized world, and it ends with orbit insertion around Ganymede, the largest moon in the Solar System.
JUICE will carry the most powerful scientific payload ever flown to the outer Solar System. It consists of 10 state-of-the-art instruments plus one science experiment that uses the spacecraft telecommunication system with ground-based radio telescopes.
JUICE’s instruments will enable scientists to compare each of these icy satellites and to investigate the potential for such bodies to harbour habitable environments such as subsurface oceans. They will also carry out observations of Jupiter, its atmosphere, magnetosphere, satellites and rings.
The launch of JUICE is currently planned for 2022. After a 7.5-year cruise toward Jupiter, which includes gravitational assists from Earth, Venus and Mars, the spacecraft will enter orbit around the giant planet in 2029.