The European Space Agency (ESA) said its Philae lander has made contact again after a five-day gap as mission controllers work to improve communications with the washing machine-sized spacecraft on a speeding comet.

Philae, which in November became the first spacecraft to land on a comet, sent its first signals in seven months last Saturday. As the comet approaches the sun, Philae's solar panels are getting enough light to revive the lander.

Philae sent more signals on Sunday but was not heard from again until today, a gap ESA says was not unexpected. In a pair of two-minute contacts 17 minutes apart, it delivered more housekeeping and status data.

ESA has sent commands to the lander's mother ship Rosetta, 112 miles from the comet, to improve communications between the spacecraft.