Lincoln Calibration Sphere 1
| Names | LCS-1 |
|---|---|
| Mission type | Radar calibration |
| Operator | MIT Lincoln Laboratory |
| COSPAR ID | 1965-034C |
| SATCAT no. | 01361 |
| Mission duration | Elapsed: 60 years, 1 month and 14 days |
| Spacecraft properties | |
| Spacecraft | LCS-1 |
| Spacecraft type | Aluminium sphere |
| Manufacturer | Rohr Corp. |
| Dry mass | 34 kg (75 lb) |
| Start of mission | |
| Launch date | May 6, 1965, 15:00:03 UTC |
| Rocket | Titan IIIA |
| Launch site | Cape Canaveral LC-20 |
| Contractor | US Department of Defense |
| Deployed from | Geocentric orbit |
| Deployment date | 06 May 1965 |
| End of mission | |
| Disposal | Re-Entry |
| Decay date | In c. 30,000 years |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Medium Earth |
| Eccentricity | 0.00055 |
| Perigee altitude | 2,786 km (1,731 mi) |
| Apogee altitude | 2,796 km (1,737 mi) |
| Inclination | 32.1° |
| Period | 145.6 minutes |
| RAAN | 1 hour 35 minutes |
| Epoch | May 5, 1965 |
The Lincoln Calibration Sphere 1, or LCS-1, is a large aluminium sphere in Earth orbit since 6 May 1965. It is still in use, having lasted for over 50 years. The sphere was launched along with the Lincoln Experimental Satellite-2 on a Titan IIIA. It is technically the oldest operational spacecraft, but it has no power supply or fuel; it is merely a passive metal sphere. LCS-1 has been used for radar calibration since its launch. It was built by Rohr. Corp. for the MIT Lincoln Laboratory.
LCS-1 is a hollow sphere 1.12 m (3 ft 8 in) in diameter with a wall thickness of 3.2 mm (0.13 in). The sphere was constructed from two hemispheres, made by spinning sheet metal over a mold. These hemispheres were fastened to an internal, circumferential hoop by 440 countersunk screws, then milled and polished. The initial finish had a surface roughness less than 10 micrometres and was expected to last for five years. Since its launch, I-band measurements have shown periodic deviations that likely correspond to one or more new surface irregularities.
Before being launched to orbit, the optical cross section of the LCS-1 was measured in L, S, C, X and K microwave bands. Four other spheres were also manufactured and measured for comparison to the one in orbit.