Quick Facts About Webb

alt text image

Primary Mirror Stats

Mirror Type:

Segmented parabolic reflector


21.6 feet (6.5 m) at its widest point


269 square feet (25 m²)


1554 lbs (705 kg)

Focal Length:

414.4 feet (131.4 m)

Optical Resolution:

0.07 arc-seconds, diffraction-limited at 2-micrometer wavelengths (0.0317 arc-second pixels)


Beryllium, with a thin coating of gold

Number of Segments:

18 segments

Observatory Stats

Operating Temperature:

–387.7° Fahrenheit (40° Kelvin; –233.2° Celsius)

Observatory Mass:

About 14,000 lbs (6,330 kg)

Sunshield Size:

70 by 48 feet (21.2 by 14.6 m)

Planned Launch:

Spring 2019

Launch Vehicle:

Ariane 5 rocket, provided by the European Space Agency

Launch Site:

The Centre Spatial Guyanais (CSG) in Kourou, French Guiana


Orbiting the Sun 940,000 miles (1.5 million km) from Earth at the Second Lagrange Point (L2)

Orbit Shape:

As seen from Earth at midnight, the Webb orbit completes a large loop of 1,000,000 km in diameter, twice a year.

Transit Time to Orbit:

About 1 month

Science Mission Lifetime:

5 years, with a goal of 10 years

Solar Array Power:

2000 watts

Maximum Data Rate (Deep Space Network):

28 Mbps

Cost at Launch:

$8 billion, plus ESA and CSA contributions

alt text image

Instrument Stats

Wavelength Coverage:

0.6- 28.5 micrometers


• Near Infrared Camera (NIRCam) (0.6–5 micrometers)

• Near Infrared Spectograph (NIRSpec) (0.7–5 micrometers)

• Mid Infrared Instrument (MIRI) (5–28.5 micrometers)

• Fine Guidance Sensors/Near-Infrared Imager and Slitless Spectrograph (FGS/NIRISS) (0.6–5 micrometers)


Webb's sunshield is the size of a tennis court.

Webb's mirror is covered in a thin layer of gold.

While Webb can't observe Mercury or Venus, it will be able to study the solar system beyond the orbit of Mars, including Mars, the outer planets, icy moons, and Kuiper Belt Objects.

Updated: Nov 15, 2016