Every telescope on the SCOB deck fights the same enemy: Earth's atmosphere. The air above us is both a blanket and a blur. It soaks up most of the electromagnetic spectrum before it ever reaches the ground, and the little that gets through is smeared by turbulent, shimmering air — the "twinkle" we call seeing. A telescope lofted above the atmosphere escapes all of this.
Putting a mirror in orbit buys four things a ground telescope can never fully have:
The trade-off: a space telescope can never be repaired on a workbench (Hubble was the rare exception), it must carry its own power and coolant, and every kilogram costs a fortune to launch. So where you park it — its orbit — is chosen just as carefully as the mirror itself.
Only two big "windows" let the sky through to Singapore's altitude: the visible band (what our eyes and the SCOB scopes use) and the radio band (what dish antennas use). Slices of the infrared squeeze through between water-vapour absorption. Everything else — most infrared, all ultraviolet, X-rays and gamma rays — is absorbed before it lands, so to study those you must go to space. That single fact explains why we have a whole fleet of orbiting observatories, each tuned to a different colour.
Each band reveals a different physical process. Cool gas and dust glow in the infrared; hot young stars blaze in the ultraviolet; million-degree gas around black holes and exploded stars shines in X-rays. No single telescope sees it all — the fleet divides the spectrum between them.
Maps the faint afterglow of the Big Bang (the cosmic microwave background) and cold hydrogen gas. Space avoids the water vapour and heat that swamp these ultra-faint signals.
Mapped the cosmic microwave background with exquisite precision, pinning down the age and composition of the Universe.
Sees through dust clouds to newborn stars, detects cool objects (planets, brown dwarfs) and stretches to the most distant galaxies, whose light has been red-shifted into the infrared. Detectors must be kept extremely cold — a key reason these live far from Earth's warmth.
6.5 m gold-coated mirror; the most powerful infrared observatory ever flown. Peers at the first galaxies and the atmospheres of exoplanets.
NASA's great infrared observatory; studied star-forming regions, distant galaxies and exoplanet weather.
Largest far-infrared mirror flown; traced how cold gas collapses into stars.
Surveyed the whole sky in infrared; later re-tasked to hunt near-Earth asteroids and comets.
The first infrared all-sky survey — discovered dust discs around stars and vast reservoirs of galactic dust.
The same light our eyes use — but far above the blur. Space gives razor-sharp images, adds ultraviolet (blocked at ground level) to reveal hot young stars, and offers the rock-steady pointing needed to measure star positions and catch tiny planet transits.
The famous one: ultraviolet through near-infrared. Its deep-field images redefined our view of the cosmos. Low orbit made Space-Shuttle servicing possible.
Charted the precise positions, distances and motions of ~2 billion stars — a 3-D map of the Milky Way. Retired to a Sun orbit in March 2025.
Stared at one patch of sky to catch the tiny dips of planets crossing their stars — found thousands of exoplanets.
Kepler's all-sky successor, surveying the brightest nearby stars for transiting planets.
Visible + near-infrared wide survey mapping billions of galaxies to probe dark matter and dark energy.
Hubble-sharp but with a field of view ~100× wider; will survey dark energy and image exoplanets. Bound for L2.
The hottest, most energetic light — from gas swirling into black holes, supernova remnants, neutron stars and cosmic explosions. Completely blocked by air, so these observatories are only possible from space, and often ride high, elliptical orbits to escape Earth's radiation belts.
NASA's flagship X-ray observatory; images hot gas around black holes and in galaxy clusters. Its long, looping orbit keeps it above the belts for uninterrupted viewing.
ESA's X-ray workhorse — high sensitivity for faint sources and X-ray spectroscopy.
Gamma-ray sky survey — pulsars, blazars and gamma-ray bursts, the most energetic events known.
An orbit is a design decision, not an accident. It's chosen to give the instrument the temperature, the darkness, the pointing stability and the communication link it needs. Here are the five homes space telescopes actually use.
Close enough to reach with a crew for servicing and to send data home easily. The trade-off: Earth fills half the sky (blocking targets), the telescope passes in and out of sunlight every orbit, and it flies through Earth's warmth — fine for visible/UV, awkward for cold infrared.
Hubble (chosen so the Space Shuttle could service it), Fermi
Passes over each spot at the same local sun-time and can keep the Sun always behind it — ideal for sweeping the whole sky in strips while keeping the telescope shaded and cool.
IRAS, WISE / NEOWISE
Climbs tens of thousands of km out, spending most of its time high above Earth's radiation belts where the view is uninterrupted for hours — perfect for long X-ray exposures. TESS uses a special orbit locked to the Moon's gravity for stability.
Chandra, XMM-Newton, TESS
A gravitational "sweet spot" that keeps the spacecraft in step with Earth as it orbits the Sun. From here the Sun, Earth and Moon all sit in roughly the same direction, so a single sunshield can block them all at once — the telescope stays permanently dark and deep-frozen. Ideal for infrared and precision surveys, with an unobstructed sky and easy communication back to Earth.
JWST, Gaia, Euclid, Planck, Herschel, Roman (2026)
The spacecraft simply circles the Sun a little slower than Earth, drifting steadily away from our planet's heat and radio noise. Gives a very stable, cold, uninterrupted environment — the catch is that it drifts ever farther, weakening the signal until the mission ends.
Spitzer, Kepler
Ground telescopes are far bigger, cheaper and upgradable, and modern adaptive optics now cancel much of the blur. But no technology can un-absorb the atmosphere: the infrared, UV, X-ray and gamma sky is invisible from Jurong at any aperture. Space and ground are partners, not rivals.
SCOB works the visible window; the fleet covers the rest
| Telescope | Band | Orbit | Sees mainly | Status |
|---|---|---|---|---|
| Hubble | Vis / UV / near-IR | Low Earth | Sharp deep-sky images, galaxies, nebulae | Active |
| JWST | Infrared | Sun–Earth L2 | First galaxies, exoplanet atmospheres, star birth | Active |
| Chandra | X-ray | High elliptical | Black holes, supernova remnants, hot cluster gas | Active |
| XMM-Newton | X-ray | High elliptical | Faint X-ray sources, spectroscopy | Active |
| Fermi | Gamma-ray | Low Earth | Pulsars, blazars, gamma-ray bursts | Active |
| TESS | Visible | High elliptical | Transiting exoplanets around bright stars | Active |
| Euclid | Vis / near-IR | Sun–Earth L2 | Dark matter & dark energy via galaxy shapes | Active |
| Roman | Vis / near-IR | Sun–Earth L2 | Wide dark-energy survey, exoplanet imaging | Launching 2026 |
| Gaia | Visible (astrometry) | L2 → solar | 3-D map of ~2 billion Milky Way stars | Science ended 2025 |
| Kepler | Visible | Earth-trailing | Exoplanet transits (single deep field) | Retired 2018 |
| Spitzer | Infrared | Earth-trailing | Dust, cool stars, distant galaxies | Retired 2020 |
| Herschel | Far-infrared | Sun–Earth L2 | Cold gas & dust collapsing into stars | Retired 2013 |
| WISE / NEOWISE | Infrared | Low Earth (polar) | All-sky IR survey, near-Earth asteroids | Retired 2024 |
| IRAS | Infrared | Low Earth (polar) | First IR all-sky survey, dust discs | Retired 1983 |
| Planck | Microwave | Sun–Earth L2 | Cosmic microwave background (Big Bang echo) | Retired 2013 |
Two teaching hooks for Friday visitors. First: you can see a space telescope with your own eyes — the Hubble Space Telescope is bright enough (around magnitude 2–3) to spot as a fast-moving "star" during a favourable pass, and it's already listed among the satellites tracked on the dashboard. Point it out and note that it's looking out while everyone looks up.
Second, the same-object comparison: pull up a SCOB eyepiece view of the Orion Nebula or a galaxy, then a Hubble or JWST image of the same target. The difference isn't a better eyepiece — it's the missing 100 km of atmosphere, plus the extra colours (infrared, UV, X-ray) that never reach Jurong at all. That's the whole story of why we build telescopes in space, in one side-by-side.